primitive telecomunication

Indian telephones

The beginning of voice on wires:

28th January 1882, is a Red Letter Day in the history of Telephones in . On this day the Telephone Exchanges in , and were declared open. The exchange at named "Central Exchange" was opened on 30-06-1882; the Central Telephone Exchange had 93 subscribers. In 1883 First telephone communication was established between and through a cable laid beneath the floating .

The independent had a few telephone lines. They were concentrated in metros like , , and .

The railway control circuits were using the phone system for trains’ movement.

            It was still a manual switching system in which every call is to be put through manually. Gradually the system spread to state capitals and the district headquarters. 

Primitive communication system 

        

A small telephone exchange was opened in a district headquarter to start with. It was placed near the market area, or some suitable place centrally located in the town. Very few open wires served the main offices like the post office, polish station, administrative offices and business houses, and some VIPs connections. All connections taken together were probably less than 50[DELs] direct exchange lines.

The manual call switching board [switch board] was simple with indicator lamps to indicate the condition of phone lines by glowing small line lamps. Lines were terminated on line terminals [hole-like jacks]. A line lamp and associated line jack were the terminals of subscribers’ lines. To interconnect the callers to called subscribers [subs], a pair of connecting cords were used.

The telephone operator has to respond to the demand of the calling sub, answering the calling sub by inserting a cord into a line jack. Ascertain the called number and connect to the called line and give a manual ring to the called sub so that he lifts the handset; thus the connection is established between the caller and the called numbers.

This was a simple manual exchange; the power supply was managed centrally at the exchange itself and it was called CBNM [central battery nonmultiple] exchange system.

Initial exchanges for telephony were of this nature, throughout the nation in prior to 1970 or so. The telephone operator was the software behind the call-switching activity.

Each subscriber was charged a monthly rent of Rupees 50/ towards the service given. The local calls were free of cast for the entire month.

Trunk circuits were established connecting with adjacent district headquarters and taluk headquarters. Some large villages were also connected with PCOs. Open wire lines [of tubular iron poles] were used. To construct open wire lines and to maintain these lines in working order; a separate staff called the line staff was recruited on a permanent basis. They were called linemen; line inspectors etc. The switching apparatus was maintained by a trained technician.

Multiple operators were used for rotational round-the-clock duties. A senior man among them has to supervise the operational activity; and manage the overall system.

The operator has to handle local calls, trunk calls, book the ticket, for trunk calls and establish trunk calls and charge the calls by noting the time of call connected and call disconnected.

These trunk calls (established) tickets were to be dispatched to the revenue accounting office in the divisional office, where the Divisional engineer’s office was established.

On the engineering side Divisional Engineer’s office, the Sub-divisional Engineer’s office, and the junior engineers’ office were established to manage the technical affairs of the working system.

 The background:

1837-telegraph

1864-existence of radio waves

1875-invention of telephone

1897-strowger exchange

1901-transmission of radio signals

1904-vaccum tube diode

1918-super heterodyne radio receiver

1948-mathematical theory of digital communication

1948-invention of transistor

1955-proposal of satellite communication

1958-silicon integrated circuit

1962-telstar satellite-bell lab

1966-use of fiber as a dielectric waveguide

1971-pocket switching theory

Bidar being the district headquarters had also a telephone system. In 1974 there were about 300 telephone lines in Bidar town. The primitive system of local telephone lines was, all overhead iron wires hanging along the local roads on tubular posts along the streets. They were terminated on a manual switchboard. The manual switching of local calls and trunk calls was done by telephone operators (TOs). Telephony was a new flourishing business undertaken by the communication ministry and the department was known as the Posts and Telegraphs (P&T) department.

          Talented taught students either of SSLC /PUC or of degree were regularly inducted or absorbed in the system, to cope up with the growth of telecommunication service.

I was a 1973 science graduate (B.Sc.) and I was inducted as TO in 1974. The  division had four districts covering , Raichir, and Bidar. local area had a 700 lines telephones system, all managed manually. The telephone operator was the blood and nerve of the operating system for putting through calls and serving each and every inquiry of the customers.

            Telephone being the fastest method of communication was established in cities and towns. The growth and modernization were slow.

            Trunk lines were constructed by erecting tubular posts along the state highways and other road networks. The Indian railways used the service of telecom for trains’ movement. The trains' control and block lines were maintained by P&T. The engineering supervisors, technicians, sub-inspectors ‘and linemen were the people to construct and maintain the trunk lines. Two separate parallel conducting wires which enable the path for the speech current to pass through them were called trunk circuits. All these local lines and trunk lines were terminated on manual switchboards and were handled by TOs.

Normally all taluka headquarters were connected to the district headquarters by trunk circuits. And Bhalki was one such taluka in Bidar district. There was a trunk line between Bhalki and Bidar along the railway route. This route was further extended to Kamalnagar, Aurad, and Santapur. Some villages were directly terminated to the board and these lines were known as PCOs (public call offices). A post office of the village houses a phone instrument and the postmaster keeps the call records. There were about 70 working lines at the Bhalki telephone exchange. There were five telephone operators to handle the telephone traffic of the town. One of them would be the head operator. He was supposed to keep all the records of calls established and dispatch the tickets to the divisional office for the calculation of call charges on individual lines. The exchange system was very simple at Bhalki. A CB non-multiple board, a small MDF, a battery room, and a carrier system of 1+3 type, were housed in a rented building. The external plant was, a bit of cable laid up to the Gunj main circle and local lines feeding the shops. The engineering supervisor groups Bidar was in charge of the system.

          The customers who used these services were billed monthly and if the bill is not paid, the line was disconnected temporarily to press the party to pay the dues. The revenue collection was thus regular and prompt. But the main problem was the manual-working, especially during night hours, human nature is to sleep but they were made to work like machines and they did not.

       These early telephone lines were of open wire type. The iron wires (galvanized) were drawn right from the switching office to the subscribers’ premises, along the streets. The trunk lines were going along the roads and they were exposed to wind currents, the rains, and the night colds and mid-day heat of summer. There was ware and tare. If the line is loose or the span length from pole to pole is kept long, the wires got contact with each other due to wind disturbances, and the line is short-circuited and hence dead. Sometimes there will be a break of conductors and supporting posts slanting due to heavy rains. These were to be attended promptly to restore the telephone services. Telegraph lines were also working between post offices. A written message was generated known as a telegram and sent to the concerned party.

            This simple system of connecting people manually by building circuits by operators from place to place as a cascade was a well-established practice of manual switching. Suppose that a subscriber at Bhalki wants to communicate with a person at Gangavathi the call is to be routed through Bidar-Gulbarga-Raichur and then to Gangavathi, the terminal destination of the called party. Since there were limited circuits between towns, there used to be delay to establish a call. There will be a lot of waiting time for a call to mature. The average waiting will be more than one hour for any trunk call. And there was no substitute or alternate method to that of calling a person in need. The marketing people, the businessmen the executives were badly in need of telephone services.

         A letter takes 4 days, a telegram takes 24 hours, and a trunk call takes 2 hours, to communicate. A trunk call is a two-way speaking system and no such facility can be had by other means of communication. Thus it was of immense use to a business to happen between two parties placed far away.

            But the service was not steady and there used to be interruptions again and again due to the lines going out of order. Physical lines running kilometers and being exposed to an open environment, caused a lot of inconvenience and the first party to face the angry customer was the on-duty telephone operator.

            A technique to increase the trunk line capacity was developed by building carrier systems on physical lines. The first one such system was a three-channel carrier system. The advent of electronic circuitry in its primitive stage gave rise to these speech carriers working in addition to the physical lines. That is if there existed a physical line between two places, it was possible to increase the circuits to a 1+3 system of trunks. This increased the availability of circuits between two stations and call waiting time was reduced to 50%. This was a milestone in manual telephony.

            Later on, automatic local exchange switches of Strowger technology were introduced in towns and district places. This reduced the burden of connecting local calls manually. The customer on hearing the dial tone has to dial the required number himself. This automatic system was built on the electro-magnetic principle and uni-selectors and two motion selectors were involved in the process of switching a local call. To monitor the working of these selectors, technicians were employed. They used to rectify the faulty switches. Here again, there was a problem of wrong switching due to the switch going faulty. Wrong switching added to the revenue bill of the customer and a cause of dispute.

            Once the internal system is made automatic, the customer has to dial the local number himself. Thus the burden of the operator is reduced to a considerable extent. He has to concentrate on trunk booking, answering incoming trunk lines to receive incoming calls from other stations, and to put-through the booked calls. Unmanned small auto exchanges of lesser capacity were terminated on these trunk boards to put through calls originating from those exchanges.

            At district head quarts, there was larger trunk traffics. Therefore, the numbers of boards were more and the trunk lines were available as multiples at many boards. The boards were called positions. At metros, there were still more positions and hundreds of operators were working continuously round-the-clock. The duty hours of an operator were normally 8 hours. They were coming to duty on shifts. This was the system of manually switching calls.

            Bulk of trunk routes was needed to handle the growing traffic between metros. The coaxial cables were laid between the major metros. Later when electronic integrated circuits were developed, new microwave systems started appearing in the field to build wireless trunk routes. The microwave towers were erected at about a distance of 50km span length. Repeaters were installed at such locations and the station was maintained with batteries and engine alternators. Between1980-85, most of the metros were connected by microwaves. This technical up-gradation gave rise to the availability of plenty of trunk lines between cities. Now, the local and trunk were automatic and subscriber trunk dialing was introduced between many cities. Thus the need for the operator is slowly eliminated from the system. The operators were surplus and they were used for miscellaneous works. The technical manpower was increased to maintain the new systems. During Rajeev Gandhi as prime minister of , one Mr.Shyam Pitroda came to and he took the task to create all electronic switching systems. Thus there onwards everything was automatic and by this time most of the surplus staff were either retired or absorbed into service center handling. There were rapid expansions everywhere and a lot of new addition of assets both internal and external systems. The working lines at district headquarters grew tenfold in a span of a decade time.

Thus the communication network grew and works were specialized and a separate internal wing was dedicated to maintain the major trunk routes. Similar to railway zones, telecom regions were established to handle the system effectively.

            All such things happened but most of the village population remained out of this facility. The demand was building up and the service was not available to villages. About 50% of the villages were not having communication links. If there are PCOs, they were not maintained as desired due to technical reasons. Efforts were made to install VPTs. But they did not serve the real purpose.

            Meanwhile, optic fiber cables were developed and being inducted into the system.

These simple optic fibers were having a very large capacity to increase the channels just by replacing the end units of trunk routers. They were cost-effective and more stable and most of the microwaves were replaced by OFC cables. In metros, multi-exchange cables, called junction cables were replaced by OFC cables. Also, interior towns in a district were connected to district headquarters by these optic fiber networks.

         As a whole when considered, lot of backside activity, for store management, activities at ITI terminals, transport of stores to local store yards, and making available when needed, all such things are to be taken into account. A place of 100 crore people, a vast territory, and a gigantic task force to make things happen. Telecom stores, zonal offices, telecom circles, and divisions were buzzing places with full of activity to organize and to implement the decisions made by heads of the task.

Tukaram Kumbar Hochakanalli 

Date of birth:     03-08-1951.

Education:   B Sc Maths and Physics.

Employment:

            1974- Telephone operator.

            1980- Telephone inspector.

            1084- Junior Engineer.

            1999- Sub Divisional Engineer.

Retired from service on 01-02-2009.

Some important changes:                                     

• Mores code telegraphy
• Manual telephony
• Electro-magnetic strowger exchanges
• Cross-bar switching systems
• Teleprinter [telex] exchanges  
• Electronic exchanges                                                                                                                                                                                                          Trunk lines:

• Open wire trunks[physical line]
• Three-channel carrier systems
• Eight channel systems
• Microwave links [line of sight communication links]
• Digital microwave systems
• Optic fiber cables links[light wave guides]

           

                                                                                                                                                               

My education and employment

Tukaram Kumbar

After independence, For the First time a new teacher was posted to my village Hochakanalli in 1960. I was sent to this new school which was running in a private building. I was declared passed the second standard within one year. From 3rd standard to 7th standard, I went to Kheni Ranjol NTMS School. The school was about 1.2 kilometers away from my residence. One Shri Gurubasappa was my maths teacher middle school.  Mathematics fascinatedme me in the school. I scored 90% of marks in maths in the 7th board exam that held in 1966.

Then I continued my High School education in Kheni Ranjol itself. l lost my father in 1967 when studying in 9th class. Passed the SSLC exam in first division in the 1969 summer. Elders conducted my child marriage after my SSLC exam.Then I studied in the BV Bhoomareddy College Bidar for four years. I was awarded National loan scolorship for my degree education. Maths and physics were my optional subjects. Earned my B.Sc. degree in 1973 from the Karnataka University Dharwad.

From 1974, I was working as a Telephone Operater in the Post and Telegraph department of India. This was a low paid job.I was dreaming for a better paid job.

After five years of initial service, by writing a departmental compitative exam, I got my first promotion as a Telephone Inspector in 1980. Worked in the Bellary division for two years. In 1983 by writing another competative exam, got my second promotion as a Junior Engineer Telecom, and worked from Raichur city for a period of 12 years    

    One Mr. Despande SDE and myself worked together for installation of new modular pillars in the Raichur under ground cable network. This system increased flexibility and became a point of cable fault isolation. We worked for transfer of MDF to PRX at Raichur switching system. Cable network was successfully loaded to PRX container exchange without interrupting working Telephone lines.

In 1999, on seniority, I was promoted as SDE Telecom, and worked in the Bidar city till my retirement from the Telecom service in 2009.

In 2000, the service sector of Telecom was re-organized as BSNL. Telecom sector was opened to private Operaters too. The BSNL era of Mobile telephony started all over the Nation. Landline Telephones started decreasing gradually. Employees were exposed to compititive environment. They were encouraged to opt for retirement. Most of the employees felt fish out of water. There was no more monopoly over Telecom Services.

The overhead Telephone lines, and the underground Telephone cables gradually started becoming absolate. The fault rate was reduced to almost nil. Mobile serve sector started groving vigorously. There after The number of personal mobile sets increased rapildly in India.

 

 

 

 

 

 

 

Earth crust composition

Earth crust composition

More than 90% on the crust is composed of silicate minerals. Most abundant silicates are feldspars (plagioclase (39%) and alkali feldspar (12%)). Other common silicate minerals are quartz (12%) pyroxenes (11%), amphiboles (5%), micas (5%), and clay minerals (5%). The rest of the silicate family comprises 3% of the crust. Only 8% of the crust is composed of non-silicates — carbonates, oxides, sulfides, etc.
Clay minerals are too small to be shown individually. Even with a light microscope you will see only mud or dust depending on whether these minerals are wet or dry. Clay minerals are silicates that are the products of weathering of other silicate minerals, mostly feldspars.
The most abundant rock types in the crust
Rocks are divided into three broad groups: igneous, metamorphic, and sedimentary rocks. The oceanic crust is largely composed of basaltic igneous rocks which are covered by a thin veneer of sediments which are thickest near the margins of the continental landmasses. The continental crust is much thicker and older. The continental crust is also much more variable and structurally very complex. Virtually all the rock types known to man occur in the continental crust. Even meteorites, xenoliths from the mantle, and ophiolites (fragment of former oceanic crust) are constituents of the continental crust because that’s where we found them.
Roughly three fourths of the continental crust is covered by sedimentary rocks and almost all of it is covered by loose sediments (soil, sand, dirt, etc.). We are most likely to encounter these materials, but it is important to understand that despite being so ubiquitous on the surface, they make up only about 8% of the whole mass of the crust. Sediments consolidate to sedimentary rocks after burial. Sand turns to sandstone, limy mud to limestone, clay to claystone. Sedimentary rocks are stable only in the upper parts of the crust. High pressure and temperature in the deeper parts metamorphoses them (minerals recrystallize) to various metamorphic rocks. The bulk of the continental crust is made of metamorphic rocks. Igneous rocks are also common on the surface in volcanically active regions, but they also occur deeper in the crust as granitic (mostly) intrusions.
Important sediments are sand, clay, mud (wet mixture of clay and fine sand), and limy mud. Widespread sedimentary rocks are limestone (2% of the crust by volume), sandstone (1.7%), claystone (4.2%) which are lithified versions of the loose sediments mentioned before. Chemical sediments like halite and gypsum are important as well, but their overall volume is clearly less than 1% of the crust. Important igneous rocks are granite, granodiorite, gabbro, basalt, diorite, andesite, etc. It is very difficult to say what is the percentage of these rocks. Important metamorphic rocks are metamorphosed equivalents of widespread sedimentary and igneous rocks. Common metamorphic rocks are slate (metamorphosed claystone), schist (met. claystone, higher grade than slate) quartzite (met. sandstone), marble (met. limestone), gneiss (met. igneous rock or sedimentary rocks), amphibolite (met. basaltic rocks).
Gypsum is an evaporite mineral. Evaporites are water-soluble chemical sediments that crystallize out of concentrated (high salinity) seawater in lagoons. 

My School Education and Service

 

Tukaram Kumbar:

I had my primary education in NTMS Kheni Ranjol, and my secondary education in TDB High School Kheni Ranjol. Passed the seventh board exam with 90% marks in mathematics. Passed SSLC in first class with 67% marks in 1969. I was a topper in my class. Lost my father when I was a ninth class student. my child marriage was held after my matriculation exam. Then I joined BVB College Bidar for one one-year PUC Science course. And continued my education for a three-year Science degree. Earned my B.Sc. degree with Mathematics and Physics as optional subjects, in 1973 summer.

My first learning in Ranjol:

I was born in 1951, on the Dasara Mahanavami day, in Hochaknalli village.  My father Gundappa was a potter. He was a very active personality and a hard worker.  He loved me, his only son too much, and he was dreaming of sending his son Tukaram, to school, so that his son would learn reading and writing skills. Olden days did not have schools in the villages of this region.

In 1960, my uncle Vithal who was a fifth-class student, asked me to come to School with him to Ranjol. I accompanied my uncle to NTMS Ranjol-Kheni. It was the first week of June and it rained during night hours. There was fresh rainwater in the open grounds of the school. The monsoon rains filled the air with delighting breath. I was admitted to the first standard and asked to sit with students in the last room. I attended this school for about our months. I learned basic alphabets and mathematical tables.

After this,  A new school was opened in my village with a single teacher. There was no school building, and I was asked to attend this new school. The school was run from a private building and the classes were arranged in a Patel's house. The school strength was about eight boys including me. The age group of boys was about seven to nine years. There was a single textbook for the first standard. I mastered reading the book within the first half of the year. During the second half, I completed reading the second standard book. Mathematics was taught on a slate. By the end of the year, It was declared that I passed the second standard.  

Kheni Ranjol was a neighboring big village, with a government New Type Middle School (NTMS). It was the only school in the neighborhood and boys from many nearby villages used to study there. Next year I was admitted to third standard at NTMS Ranjol Kheni.

For my admission at Ranjol, one Mr. Basavanthrao Police Patil accompanied my father to the school. While admitting me, the school authorities insisted that I should join for the second standard. But the Patel wanted me to be admitted to the third standard. They tested my maths skills by giving me an assignment, a subtraction problem. I solved it wrongly. So after much discussion, they concluded that they would allow me in the third standard for the first three months. If I failed the quarterly exam, I had to go back to the second standard. If I cleared the quarterly examination, I may continue to the third standard. I cleared the quarterly exam. Not only that, I emerged first to the class, in the annual examination. 

The school was about 1.25 km away from my village and I walked up and down on school days. But the school days were too difficult for four months of the rainy season, and I used to carry a plastic cover to protect myself from rain. After 4-30 pm when we were released to go to our homes, I used to walk barefoot, and on several occasions, rain chased me and I was fully wet, except my books and notebooks.

Mr. Basavanappa S was our headmaster. He was a very disciplined personality and a good timekeeper. One Mr. Gurubasappa was my mathematics teacher. I was very much impressed by his way of explaining mathematics principles. Mr. Gurubasappa was the main person to shape my character. Right from third to seventh standard, he taught me in the classrooms. Any topic he taught was impressive and was fully crystal clear; whether it be poetry, prose, or mathematics; it would be fascinating. 

I was very lucky to have such a dedicated teachers’ team and a well-built school with plenty of space for a playground. Football and valley ball were my favorite sports. From third standard to seventh standard, I was the topper in my class and always stood first among my classmates.  

During the academic year 1965-66, I passed the 7th board exam with 90% marks in mathematics. This was the subject that I loved a lot and used to spend time, solving problems of simple interest, and problems related to ratios and proportions. In 1969, I passed the 10th board, the SSLC exam, in first class, with 67% marks.

I lost my dear father in 1967 October. It was a suicide. He was cheated in a land acquisition case.  My mother was my guardian. She was sick and there was no one to support us financially. My mother was thinking about my future and she decided to conduct my marriage, though I was still a boy. In the first week of June 1969, my marriage was conducted at Srimandal village, near Janawada. The In-laws gave me a10 gram gold ring. The Srimandal village was on the banks of the Manjara River, which separated Telangana from Karnataka state.

My college education:

Though I had no money, I was dreaming of going to college for higher education. I sold 10g gold that was offered in my marriage and secured admission to the BVB College Bidar as a PUC Science student in June 1969. It was the only college in Bidar city. To start with, I became a roommate of my brother-in-law, Shri Gundappa Srimandal who was a BA final-year student. We used to cook our daily food. I had no money to get textbooks. Things were not that much easy. Spent six months of PUC Science without reference books on basic physics. Yet I stood second to my college in the final PUC exam.

Passed the one-year PUC Science, with 58% marks, in 1970 summer. I was the second topper in my PUC batch. Out of 300 students, only 90 students got through the one-year pre-university course.

I was awarded free-ship, after my PUC Science results, and the money that I paid to the college as a tuition fee was refunded. This same money, I used for next year's admission fee for B.Sc. part-one course.  Then I applied for the National loan scholarship and was selected for this. I was awarded the National loan scholarship for my entire graduation period with a 4% simple interest. I used to get 720 rupees per year. I could purchase relevant textbooks and medicine for my ailing mother. She was infected by TB.

In 1972 there was a drought, and surviving was a problem. I was in my degree final year. I also did not receive the scholarship installment amount for the 1972-73 year. I borrowed 200 rupees from a relative called Mukund Sultanpur to pay the college tuition fee. For my daily food needs at Bidar, my Grandmother Narasamma gave her (a 4-gram) nose ring. I sold it to live in Bidar, till the final year degree exam was conducted in the summer.

Passed B.Sc. in the second division with 56% marks in the 1973 summer. Thus I completed my science degree from Karnataka University. Mathematics and Physics were my optional subjects. 

Just after my degree exam, I was asked to take "summer coaching" to the children of Mali-Patel, Mr. Shamrao of Rekulagi Village. I worked as a tutor for a month in his home. Patil Shamarao gave me some food grains that I needed to survive the famine. Survival was a challenge due to famine in this region.

Then, I worked as a literate mazdoor in the PWD division office Bidar, in a famine relief fund. We (my mother and wife) survived on this little pay of Rs 100/- per month, for almost five months in 1973.

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Tukaram Kumbar:

(A summary of my education)

I was born in 1951, on the Dasara Mahanavami day, in Hochaknalli village. Olden days did not have schools in villages. In 1960, my uncle Vithal asked me to come to School with him to Ranjol. He was a student of the fifth standard. I was admitted to the first standard in Kheni Ranjol. After about four months, a new school was opened in my village with a single teacher. I was asked to attend this new school. There was a single book for the first standard. I mastered reading the book within the first half of the year. During the second half, I completed reading the second standard book. It was declared that I passed the second standard. 

Next year I was admitted to third standard at NTMS Ranjol Kheni. The school was about 1.25 km away from my village and I walked up and down on school days. From third standard to seventh standard, I was the topper in my class and always stood first in merit among my classmates. During the academic year 1965-66, I passed the 7th board exam with 90% marks in mathematics. Both my parents Gundappa andTippamma were illiterate.

I joined TDB High School in Kheni-Ranjol itself. I was awarded a fifty rupee merit scholarship. But I lost my dear father in October 1967, when I was a ninth-class student. It was a suicide. He was cheated in a land acquisition process. In 1969, I passed the 10th board, the SSLC exam, in first class, with 67% marks. My child marriage was conducted at Srimandal village with Sharanamma, in the first week of June 1969.

I was dreaming of going to college for higher education. I sold 10g gold that was offered in my marriage and secured admission to the BVB College Bidar as a PUC Science student in June 1969. I Passed the one-year PUC Science, with 58% marks in 1970 summer. I was the second topper in my PUC batch. Out of 300 students, only 90 students got through the annual board exam, the one-year pre-university course.

On my merit and poor financial conditions, I was awarded the National loan scholarship for my entire graduation period with a 4% simple interest. I used to get 720 rupees per year. I Passed my B.Sc. in the second division with 56% marks from Karnataka University in the 1973 summer. Mathematics and Physics were my optional subjects in the degree. 

My appointment in the P and T Department:

I applied for a telephone operator’s job in the Posts and Telegraphs department, in response to a paper advertisement. The Posts and Telegraphs department recruited me as a telephone operator on a merit basis. After two months of induction training at Gulbarga, they posted me at Bhalki telephone exchange as a telephone operator. And this was the turning point in my life, as I could live independently on my earnings. My first salary was Rs 317 per month.

 After completing four years of service, as a telephone operator, I applied for a departmental competitive examination, for the post of Phone Inspector. My degree subjects were mathematics and physics, and these helped me in my competitive examination. I cleared the "Phone Inspector" exam just by reading for a few days. After six months of training at RTTC Hyderabad, I was posted as a Phone Inspector at Sandur telephone exchange, in the Hospet Sub Division. It was 1980 when I was living in Sandur with my family. By then, I had two kids. I was the in-charge officer of the Sandur telephone exchange. It was a manual telephone exchange with a CBNM switchboard. Donimalai Auto Exchange was parented to this Sandur telephone exchange.

while at Sandur, I started preparations for the competitive exam for the post of ‘Junior Engineer’. This time studied well in advance, and I was ready to face the examination. Applied for the post, when called for; appeared for this examination at Bellary Centre, and I was selected for the ‘Junior Engineers’ post, this time, from the Bellary division. I did not believe the news of my selection to a higher level. I was the happiest man on that day. then, I underwent a fourteen-month training course at RTTC Trivandrum, in Kerala, during 1982-1983.

I served almost twelve years at Raichur and most of the service was on the external plant, the cable network.

In 1996 I was transferred to the Bidar district when the C-DOT XL digital exchange switch was installed recently at Bidar. A lot of external work was pending and I planned and implemented the plan with the cooperation of controlling officers. I too was promoted to TES Group B Officer's post in 1999 on seniority. I worked as a commercial officer in the TDM office in Bidar for one year. Then on regular absorption, I was posted as S.D.O. Phones Bidar.

My School and Service

                   My school  and service                                           

Tukaram Kumbar B. Sc.

During the year 1960, my uncle Vithal used to go to primary school at Ranjol kheni. He invited me to join the school at Ranjol, as there was no school in our village Hochaknalli. One day, after consulting my grandmother, I followed Vithal to school.  I was admitted to the first standard in NTMS Ranjol Kheni. It was the first week of June and it rained during night hours. There was fresh water in the open grounds of the school.

The building was L-shaped and it was a concrete building. I was impressed by the modern way of new buildings constructed outside the village of Ranjol kheni. This place was about one kilometer away from my residence at Hochknalli. We used to walk barefoot to school on a narrow mud road. This was a modern school situated in the Centre of about ten villages. Boys from different villages used to study here. The surrounding villages were Rekulgi, Mangalgi, Talmadagi, sitalgeri, Hajjargi, sirkatnalli, etc. One Mr. Gurubasappa was my class teacher for the first standard. He was a young and fresh teacher, who used to teach mathematics. By the time I finished first term, a new teacher was posted in my village. And therefore I was asked to join new school in my own village Hochaknalli. I did so and learned the alphabet. The strength of students was limited to around ten boys of similar age groups. Among these students, two of us started reading the first standard book and we two completed this textbook and were given a second standard book in the same academic year to study. So by the end of the year, we were declared passed the second standard.

The next year I was again sent to Ranjol Kheni in order to admit me to third standard. The old class teacher Mr. Gurubasappa identified me and he did not agree with the proposal as I was a first standard student in that school during the previous year. He asked me to solve a small problem on subtraction, and I did it with a wrong answer. There was an agreement among the teachers and my parents that I would be admitted to the third standard, and if I failed the quarterly examination, I would have to go back to the second standard only. If I get through, I shall continue in the third standard. I got through the quarterly examination and in the final exam I stood first in my class. After that, I used to be the topper in my class up to SSLC.

I got through SSLC in the first class in 1969 April. I was the fifth student to get an SSLC pass from my village after Indian independence. Mr. Shivareddy, Shankar Reddy, Hemreddy D, and Hemreddy S were my seniors from my village. I was asked to marry a girl from a far-off village Srimandal in the summer vacation after the SSLC exam. It was a child marriage. I lost my dear father when I was a 9th student. It was a great loss as the family lost a bread-earning member, unexpectedly. My father was a potter and active member of the village. My grandmother was the head of the family. We used to talk Telugu in our home. Most of our relatives were from Telangana.

Gundappa kumbar: my father,

Tippamma kumbar: my mother,

Narasamma kumbar: grandmother;

                       

   

After SSLC, I joined a science college at Bidar and got through pre pre-university course in science in 1970.

Thereafter I continued my education with the help of a National loan scholarship and completed my BSc in 1973. I studied mathematics and Physics as my optional subjects.

I was appointed as a telephone operator in 1974 and was posted to Bhalki. Worked at Bhalki for five years [1979] and wrote a competitive examination for the post of telephone inspector and was selected.

I underwent six-month training at RTTC Abids Hyderabad. Then I was posted to Sandur in Bellary district as a Phone inspector. I was the officer in charge of the telephone exchange at Sandur.  Sundur manganese and iron ores was a famous ore company managed by M. Y. Ghorpade, the Maharaja of Sandur.

Worked here for one year 1980-81, and again wrote the competitive exam for the post of Junior Engineer and was selected. I underwent one year of training at RTTC Trivandrum Kerala and was posted to Raichur Telephones, as a Junior engineer in 1983-84. It was a long stay at Raichur for twelve years.

I migrated to Bidar in 1996 on mutual transfer. In 1999, I was selected for the post of Sub-divisional Engineer and worked as S.D.O.Phones, at Bidar till my retirement in 2009 February.

During 34 years of service, I saw a lot of up gradations in the department; from manual to automatic system of call switching. I have seen Vigorous expansions of telephone networks in India. After 1990 the systems were digitalized all over the country. Call switching was on STD. customer could dial to anybody at any instant of time all over the nation.

After 2000 mobile networks were installed all over the nation by many companies on liberalization to private operators. Telephony became cheaper and affordable to the common man. Nowadays more than 50% population owns a mobile set.

photosynthesis

Photosynthesis

The Light dependent reactions:

 A light-dependent series of reactions which occur in the grana, and require the direct energy of light to make energy-carrier molecules that are used in the second process:

• light energy is trapped by chlorophyll to make ATP (photophosphorylation)
• at the same time water is split into oxygen, hydrogen ions and free electrons:
  2H2O --->  4H+ + O2 + 4e- (photolysis)
• the electrons then react with a carrier molecule nicotinamide adenine dinucleotide phosphate (NADP), changing it from its oxidised state (NADP+) to its reduced state (NADPH):
  NADP+ + 2e- + 2H+  -->  NADPH + H+

An electron transfer system (a series of chemical reactions) carries the two electrons to and fro across the thylakoid membrane. The energy to drive these processes comes from two photosystems:

• Photosystem II (PSII) (P680)
• Photosystem I (PSI) (P700)

In the first photosystem (Photosystem II, PSII):

• photoionisation of chlorophyll transfers excited electrons to an electron acceptor
• photolysis of water (an electron donor) produces oxygen molecules, hydrogen ions and electrons, and the latter are transferred to the positively-charged chlorophyll
• the electron acceptor passes the electrons to the electron transport chain; the final acceptor is photosystem PSI
• further absorbed light energy increases the energy of the electrons, sufficient for the reduction of NADP+ to NADPH

The oxidised form of nicotinamide adenine dinucleotide phosphate (NADP+)

The reduced form of nicotinamide adenine dinucleotide phosphate (NADPH)

  

Light reactions occur mostly in the thylakoid stacks of the grana. Here, sunlight is converted to chemical energy in the form of ATP (free energy containing molecule) and NADPH (high energy electron carrying molecule). Chlorophyll absorbs light energy and starts a chain of steps that result in the production of ATP, NADPH, and oxygen (through the splitting of water). Oxygen is released through the stomata. Both ATP and NADPH are used in the dark reactions to produce sugar.

Dark reactions occur in the stroma. Carbon dioxide is converted to sugar using ATP and NADPH. This process is known as carbon fixation or the Calvin cycle. The Calvin cycle has three main stages: carbon fixation, reduction, and regeneration. In carbon fixation, carbon dioxide is combined with a 5-carbon sugar [ribulose1,5-biphosphate (RuBP)] creating a 6-carbon sugar. In the reduction stage, ATP and NADPH produced in the light reaction stage are used to convert the 6-carbon sugar into two molecules of a 3-carbon carbohydrate, glyceraldehyde 3-phosphate. Glyceraldehyde 3-phosphate is used to make glucose and fructose. These two molecules (glucose and fructose) combine to make sucrose or sugar. In the regeneration stage, some molecules of glyceraldehyde 3-phosphate are combined with ATP and are converted back into the 5-carbon sugar RuBP. With the cycle complete, RuBP is available to be combined with carbon dioxide to begin the cycle over again.

The biochemical conversion of CO2 to carbohydrate is a reduction reaction that involves the rearrangement of covalent bonds between carbon, hydrogen and oxygen. The energy for the reduction of carbon is provided by energy rich molecules that are produced by the light driven electron transfer reactions. Carbon reduction can occur in the dark in and involves a series of biochemical reactions that were elucidated by Melvin Calvin, Andrew Benson and James Bassham in the late 1940s and 1950s. Using the radioisotope 14C, most of the intermediate steps that result in the production of carbohydrate were identified. Calvin was awarded the Nobel Prize for Chemistry in 1961 for this work 

Semiconductor Manufacturing

 

Semiconductor manufacturing:

Wafer fabrication, also known as semiconductor fabrication or semiconductor manufacturing, involves the process of creating integrated circuits (ICs) on semiconductor wafers. The process is highly complex and involves various steps, including chemical processes. Here's a brief overview of some key chemical aspects of wafer fabrication:

1. Cleaning:
   • Chemical Cleaning: Wafers are subjected to various chemical cleaning processes to remove contaminants and particles. Common cleaning solutions include RCA cleans (a mixture of deionized water, hydrogen peroxide, and ammonium hydroxide), piranha solution (a mixture of sulfuric acid and hydrogen peroxide), and other specialized cleaning agents.
2. Photolithography:
   • Photoresist Application: A light-sensitive material, called photoresist, is applied to the wafer. This involves a process where a liquid containing the photoresist is spin-coated onto the wafer.
   • Exposure and Development: The wafer is exposed to ultraviolet light through a photomask, creating a pattern on the photoresist. Chemical developers are then used to develop the exposed areas, revealing the desired pattern.
3. Etching:
   • Dry Etching: Plasma etching is often employed, involving the use of reactive gases to remove material from the wafer. Common gases include fluorine-based compounds.
   • Wet Etching: Chemical solutions are used to selectively remove material from the wafer. Acidic or alkaline solutions may be employed, depending on the material to be etched.
4. Deposition:
   • Chemical Vapor Deposition (CVD): Thin films are deposited onto the wafer using precursor gases. For example, silicon dioxide can be deposited using silane gas.
   • Physical Vapor Deposition (PVD): Metal films are deposited using physical methods such as sputtering.
5. Doping:
   • Ion Implantation: Doping involves introducing impurities into the semiconductor to alter its electrical properties. Ion implantation is a common method, where ions of dopant elements are accelerated and implanted into the wafer.
6. Annealing:
   • Rapid Thermal Annealing (RTA) or Furnace Annealing: Annealing processes use heat to activate dopants and repair crystal damage. RTA is a quicker process involving rapid heating and cooling.
7. Chemical Mechanical Polishing (CMP):
   • Polishing: CMP is used to planarize the wafer surface by removing excess material. Abrasive chemicals and mechanical forces are applied in this process.
8. Final Cleaning:
   • Final Cleaning Steps: After all the processes, a final cleaning step is often performed to remove any residues or contaminants that may have accumulated during fabrication.

These are just a few examples, and the actual processes can vary based on the specific technologies and materials used in semiconductor manufacturing. The chemistry involved in wafer fabrication is highly specialized and plays a critical role in producing high-performance integrated circuits.

The history of semiconductor fabrication:

The history of semiconductor fabrication is a story of continuous innovation and technological advancement, which has led to the development of ever smaller and more powerful integrated circuits. Here's an overview of key milestones in the history of semiconductor fabrication:

1. First Semiconductors (1940s): Semiconductors like germanium and silicon were first used in experimental electronic components during and after World War II. Early semiconductor devices included diodes and point-contact transistors.
2. The invention of the Transistor (1947): In 1947, physicists John Bardeen and Walter Brattain, with their supervisor William Shockley, invented the first practical point-contact transistor at Bell Laboratories. This marked a significant advancement over vacuum tubes in electronics.
3. Silicon Dominance (1950s): Silicon began to dominate the semiconductor industry due to its superior electrical properties and the development of the planar process, which allowed for the creation of reliable silicon transistors.
4. Integrated Circuits (1960s): Jack Kilby of Texas Instruments and Robert Noyce of Fairchild Semiconductor independently developed the integrated circuit in the early 1960s. This technology allowed multiple transistors to be fabricated on a single silicon wafer, revolutionizing the electronics industry.
5. MOSFET and Microprocessors (1970s): The Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) was developed, becoming the foundation for most digital integrated circuits. Intel introduced the first microprocessor, the 4004, in 1971.
6. CMOS Technology (1970s-1980s): Complementary Metal-Oxide-Semiconductor (CMOS) technology became prevalent due to its low power consumption and high noise immunity. It's still widely used in modern integrated circuits.
7. Shrinking Feature Sizes (1980s-Present): Moore's Law, formulated by Gordon Moore in 1965, predicted that the number of transistors on a semiconductor chip would double approximately every two years. This prediction largely held true until the 2010s, with continuous advancements in lithography and process technology allowing for ever smaller features on chips.
8. Advanced Materials and Techniques (2000s-Present): As transistors reached nanoscale dimensions, the semiconductor industry turned to advanced materials and techniques like FinFETs and 3D packaging to maintain performance and power efficiency.
9. Emergence of Foundries (2000s-Present): Companies specializing in semiconductor fabrication, known as foundries (e.g., TSMC, GlobalFoundries), became major players in the industry, offering manufacturing services to fabless semiconductor companies.
10. Quantum Technologies (Ongoing): Researchers are exploring new materials and techniques, including quantum dots, spintronics, and quantum computing, to take semiconductor technology beyond the limits of classical physics.

The history of semiconductor fabrication is marked by a relentless drive for miniaturization, increased performance, and reduced power consumption. These advancements have had a profound impact on the electronics industry, enabling the development of everything from microprocessors and memory chips to smartphones, laptops, and the Internet of Things (IoT) devices.

Popular semiconductor foundries:

As of my last knowledge update in September 2021, several semiconductor foundries play key roles in the global semiconductor industry. These companies specialize in the fabrication (manufacturing) of semiconductor devices on behalf of other companies that design and market the chips but don't necessarily own their own fabrication facilities. Here are some popular semiconductor foundries:

1. Taiwan Semiconductor Manufacturing Company Limited (TSMC): TSMC is one of the largest and most advanced semiconductor foundries in the world. Headquartered in Taiwan, TSMC is known for its cutting-edge process technologies and serves a wide range of customers globally.
2. GlobalFoundries: GlobalFoundries is a multinational semiconductor foundry with manufacturing facilities in the United States, Germany, and Singapore. It was created as a spin-off from AMD's manufacturing operations.
3. Samsung Foundry: Samsung, a major electronics conglomerate based in South Korea, has a semiconductor division that includes a foundry business. Samsung Foundry offers advanced process technologies and manufacturing services.
4. United Microelectronics Corporation (UMC): UMC, headquartered in Taiwan, is a leading global semiconductor foundry. It provides a variety of process technologies and serves a diverse range of customers.
5. SMIC (Semiconductor Manufacturing International Corporation): SMIC is a semiconductor foundry based in China. It offers a range of fabrication services and has been expanding its capabilities in recent years.
6. Tower Semiconductor: Formerly known as TowerJazz, this Israeli company operates as a specialty foundry, providing analog semiconductor manufacturing services.
7. Intel Foundry Services (IFS): Intel, a major player in the semiconductor industry, has entered the foundry business under the name Intel Foundry Services. It aims to provide advanced manufacturing services to a broad range of customers.
8. IBM Microelectronics: While IBM is not primarily a foundry, it has historically been involved in semiconductor research and development. IBM has occasionally offered foundry services to external clients.
9. Semiconductor Manufacturing South Africa (SMSA): This is a semiconductor foundry located in South Africa, providing services in the areas of chip design and manufacturing.