Traffic Service Position System

Traffic Service Position System (TSPS) was developed by Bell Labs in Columbus, Ohio to replace traditional cord switchboards. The first TSPS was deployed in 1969 and used the Stored Program Control-1A CPU, "Piggyback" twistor memory (a proprietary technology developed by Bell Labs similar to core memory) and IGFET Insulated Gate Field Effect Transistor solid state memory devices similar to DRAM Dynamic Random Access Memory.

The TSPS system utilized special analog trunks that originated at Class 5 End Office circuit switch systems and Class 4 Toll Access circuit switch systems that were connected to Class 3 Primary Toll circuit switch systems such as the 4A-ETS/PBC and 4ESS switch systems. The TSPS system did not perform switching between the originating end office switch and the toll switch for the subscriber voice path.

The TSPS system included a feature known as "Remote Trunking Arrangement" or (RTA) that consolidated the trunk connection at the originating switch and provided a switched connection to a telephone operator only as required for a short duration at the beginning of a call to obtain billing information or at the end of a call in which the caller requested "time and charges". See the Bell System Technical Journal for several articles on the TSPS system and RTA enhancement. Some telecom manufacturers wrongly claimed intellectual property rights in the late 1990s on the RTA concept developed by Bell Labs in the 1970s.

The TSPS system provided a temporary switched connection to a Toll Operator who helped facilitate calls requiring human assistance such as Person-to-Person, Collect, Third-Party-Billed, and Hotel Billing. The TSPS system supported up to seven "Chief Operator Groups" (COGs) with each COG supporting up to 31 operator consoles. Operator consoles initially used nixie tube displays that were quickly replaced by light-emitting diode displays due to reliability issues.

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