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| Carrier Transmission System |
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| A. |
Expansion of open wire carrier transmission equipment.
In order to maximize the function of the expensive long distance telecommunication lines, multiplexing technology was generally employed, and telephone carrier equipment was introduced to increase line usage rate and enhance connection quality. Just after Taiwan was recovered from the Japanese, the Taiwan Railway Administration owned only one set of three way open wire carrier telephone system with visible cable lines between Taipei and Changhua. Taking advantage of the Taiwan Sugar Company's trade surplus with Japan in 1951, 6 sets of single way open wire carrier telephone units were procured. These units were installed at various exchange stations which effectively eased the long distance line congestion problem. In 1961, for the CTC signal construction project between Changhua and Tainan , one unit of 8-way open wire carrier telephone equipment, manufactured by the Swedish Ericsson Company, was imported. By 1962, 2 units of three way open wire carrier telephone units made by the French firm CTC was procured through U.S. loans. These units were installed in the sections between Taipei to Changhua and Changhua to Kaohsiung . |
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To effectively implement the automatic dialing system for long distance telephone connections, various telephone exchange devices had to be equipped with automatic function, as well the number of connection lines between exchange stations needed to be increased and improved. |
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However, the original carrier equipment was outdated and the capacity was too small to accommodate the automatic dialing system. Thus, since 1966, 9 units of new 12-way telephone open wire carrier devices that incorporated electronic transistors were imported from Japan in lots according to the automation schedule of various districts. These units were applied at the stations to serve as connection lines. From there on, the number of connection lines greatly increased, providing adequate transmission quality as well as making automatic dialing comprehensively effective. |
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| B. |
Installation of coaxial cable carrier
For the railway electrification construction, the latest coaxial cable carrier system was installed in coordination with cable underground construction, replacing all visible cableways of the original open wire carrier equipment of the Western Mainline. This new system was contracted to the British firm GEC, and it was classified under the P 4M specifications of the CCITT. The maximum circuit capacity of each system amounted up to 960 channels. During the initial phase, 8 systems were installed based on actual needs, offering 545 channels. The circuit quality is apparently much better than visible open wire carrier; it is also more stable and reliable. |
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The capacity is also significantly greater which is expected to meet with the telecommunications needs for the next few decades. |
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| C. |
Installation of subscriber carrier
While implementing an automatic long distance dialing system, individual frequency calling devices were introduced; all the telephone units at each station were incorporated into the automatic exchange system. The limitation of the system was that 8 telephone users had to share one pair of lines (party line); no more than two users were able to access outbound lines simultaneously. Consequently, busy signals were frequent. Therefore, at the time of the railway electrification in accordance with the combined coaxial cableway underground construction, 75 systems of subscriber carrier devices (8 lines to each system) were installed for the entire cableway system through the outer lines of cables in place of individual calling function. These new equipment allowed users to access exclusive circuits and thus improved the outbound connection between all the stations. |
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| D. |
Installation of PCM (Pulse Code Modulation)
Along with technological development in electronics and computers, carrier technology has been upgraded from analog to digital, and the PCM carrier method has also become the main stream of the carrier equipment. Circuit quality is finer than conventional analog devices and equipment cost is also lower. It offers the advantage of direct linking with computers. Therefore, since the construction of the North Link Railway, all the new carrier engineering projects of the Taiwan Railway Administration opted for PCM system. Taiwan manufactured PCM carrier equipment was used in the Eastern Mainlines including Yilan, North link and Eastern line, providing a low cost quality transmission circuit. |
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Currently, this route has 24 systems of PCM with 480 channels and has become the main circuit for the Eastern Railway telecommunications transmission. Upon completion of the cable underground projects for the Pingtung route and South Link Railway, a PCM system was also installed to link the Western and Eastern lines together as an island wide telecommunications network. |
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| E. |
Installation of digital line multiplication system
Since the Taiwan Railway Administration began a comprehensive computerized reservation and ticketing system in 1983, the need for telephone circuits have dramatically increased. A digital line multiplication system was thus introduced for regional users of various railway routes. |
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This equipment is particularly essential for line congestion sections where more cable lines could not be added at once. With the equipment, one pair of actual lines can be divided into at least 4 channels, yielding 12 terminals for 12 users. This facility serves to ease the cable deficiency problem, and also gradually replaces the subscriber carrier system installed during the process of island wide railway electrification engineering. |
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| Automation of Telephone Exchange |
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| After the recovery of Taiwan , the TRA had only one set of Siemens model automatic telephone switchboard with 500 lines, the function of which was only for outbound communication within the city area. Long distance and local calls relied on manual operation on the magnetic or common battery switchboards installed only at major stations. For minor stations along the route, magnetic telephone units were installed, and thus several stations would have to share one pair of open wires which were connected to the telephone switchboard. Calls were made through energizing the generator by hand to send out specific signals to alert a particular recipient. Telecommunications were exceedingly inconvenient and inefficient at the time. |
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| By 1961, the telephone exchange need had far exceeded service capacity, even worse, breakdowns were frequent. At the same time, the rapid development of railway transport also dictated the increasing needs of telecommunications. As a result, the ware hou se for the TRA General Affairs Department was duly altered into an exchange operating room. A brand new Siemens Automatic exchange was installed gradually. It featured signal calling changed into individual person to person telephones controlled by DC impulses. |
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| The calls were automatically transferred by a new automatic switchboard lines. Badu, Jhongli and Tamsui were incorporated into the automatic service range. This measure enhanced telecommunication efficiency, and was a great help to the Taiwan Railway Administration's development towards an automatic dialing system for long distance calls. |
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| In order to improve the long distance call service of the entire route, save manpower, and enhance telecommunications efficiency, the TRA planned to carry out the telephone operation automation for the whole line, and thus prompted the Electrical Engineering Department to begin a Comprehensive Out line for Taiwan Railway Long Distance Automatic Dialing Project. The route was divided into 3 districts: Taipei was the central office for the Northern District, covering 3 end offices at Ilan, Keelung and Hsinchu; Changhua was set as the central office for the Central district, covering Taichung and Chiayi end offices; Kaohsiung was the central office for the South district with Tainan and Pingtung as end offices. Hualien was planned as the centre for the East with Taitung as its end office. The 12-way open wire devices were facilitated between the central office and their end offices to reinforce connections, forming △-Y type circuit network. The Comprehensive Route Long Distance Automatic Telephone Dialing Project was duly established based on this network. User numbers of all regions were preset, allowing this project to progress systematically. |
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| The Long Distance Call Automatic Dialing Project was initiated in 1961; owing to a financing problem, the project took a full decade to complete. Nevertheless, the Taiwan Railway Administration was proud of their independent financing as well as efficient technological planning, design and construction. Furthermore, the exchange devices were also domestically manufactured by Taiwan Telecommunications. It was a major telecommunication accomplishment by collective national effort that pioneered Taiwan 's long distance automatic dialing technology. |
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| The engineering and construction stages of the Taiwan Railway Long Distance Call Automatic Dialing System are as follows: |
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| A. |
1961 - Completed 800 Siemens automatic switchboard and put into use in the Northern region |
| B. |
1962 - Completed 300 and 100 Siemens automatic switchboard in Kaohsiung and Pingtung respectively and put into use in these regions |
| C. |
1966 - Completed 200 and 300 lines Stronger automatic switchboard in Taichung and Changhua respectively and networked functions between the five offices of Taipei , Taichung , Changhua, Kaohsiung and Pingtung. |
| D. |
1968 - Completed 200 and 200 lines Stronger automatic switchboard in Hsinchu and Keelung respectively. Both offices also became end offices of the Northern region and joined in the Long Distance Call Automatic Dialing System |
| E. |
1969 - Completed 200 and 100 grid automatic switchboards in Chiayi and Tainan respectively, and incorporated into the central system |
| F. |
On 21st Sept., 1970 - Initiated the operation of 200 lines crossbar switchboards in Yilan and incorporated into the toll dialing system. The Western line telephone system of TRA was completely automatic. |
| G. |
In coordination with railway electrification and the construction of Nangang Passenger Transport Yard, 100 lines of crossbar switchboards were installed.
The sequential models at Kaohsiung and Changhua were replaced with crossbar. At the same time, expansions to 600 and 500 lines in Kaohsiung and Changhua respectively were also executed. The two dismantled switchboards were then relocated to Taipei , Taichung , Hsinchu and Keelung for facility expansions.
In this engineering project, 1,350 lines were added, and individual calling machines made way for canceled installation of subscriber carrier equipment. Each station duly upgraded into independent circuit; a total of 287 long distance call transfer devices were installed at the offices to strengthen long distance call automatic dialing operation. |
| H. |
Incorporated into the Eastern Line railway expansion project in 1982, one crossbar switchboard was installed in Hualien and Beinan, of 600 and 300 lines respectively. The Eastern Line railway was thus integrated into the local call automatic dialing system. Thus, the Eastern and Western Lines were connected. |
| I. |
Along with the Taipei City railway underground project in 1986, digital electronic switching was introduced for the first time. They were installed in Nangang Passenger Terminal to replace the crossbar switchboards. This event marked TRA ' s advancement into the electronic era. |
| J. |
After the introduction of digital electronic switching at Nangang, TRA proceeded at once to update all switching devices island wide. Replacement in Hualien in May 1994, made all 13 exchanges nationwide digitized. |
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