. The Bell System technical journal . DECODERS OPERATORTANDEM POSITION SEMI-MECHANICALTYPE KEYSET Fig. 6âPanel sender tandem system. Figure 6 shows schematically the latest type of panel sender tandemsystem. Figure 7 is a photograph of the operators positions at Sub-urban Tandem, one of the panel tandem systems in New York City,while Fig. 8 shows the area served by this system. An early type of panel sender tandem system known as the semi-mechanical system is in use in New York City. It consists both of anoperator tandem and a full selector tandem. The former has opera- TANDEM OPERATION IN TH
. The Bell System technical journal . DECODERS OPERATORTANDEM POSITION SEMI-MECHANICALTYPE KEYSET Fig. 6âPanel sender tandem system. Figure 6 shows schematically the latest type of panel sender tandemsystem. Figure 7 is a photograph of the operators positions at Sub-urban Tandem, one of the panel tandem systems in New York City,while Fig. 8 shows the area served by this system. An early type of panel sender tandem system known as the semi-mechanical system is in use in New York City. It consists both of anoperator tandem and a full selector tandem. The former has opera- TANDEM OPERATION IN THE BELL SYSTEM 393 tors positions equipped with key sets having a row of keys for each ofthe last four digits and the party line letters in subscribers numbers,and, in addition, there are coordinate routing keys for selecting trunkgroups to the various ofifices either inside or outside the New YorkCity numbering plan area. In the more recent type of panel sendertandem system, trunk groups to offices outside the Tumibcring plan area. Fig. 7âPanel sender tandem operators positionsâSuburban TandemâNew York City. are given 3-digit codes which do not conflict with office codes within thenumbering plan area, and trunk selection is made by setting up thesecodes on the key set. The trunks to the operators positions of thesemi-mechanical tandem are on a straightforward key-listening basisand do not have the call distributing feature. Frequently, it is found desirable in cities served by panel centraloffice equipment to consolidate the traffic, originating in one centraloffice building and destined to a number of central offices in one or moredistant buildings, over a single group of trunks to a distant office whichserves as a distributing point. This is done by placing panel officeselectors at the distant point. Such equipment constitutes an officeselector tandem and is arranged to complete connections incoming andoutgoing over panel dial trunks only. In all cases the connections are
Size: 2060px × 1213px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
