never produced. TXE6 TXE6 was an electronic common control exchange that was designed to extend Strowger exchanges, and known as the Electronic Reed Selector System or Reed Group Selector (RGS). Only two were built: one in London and the other at Leighton Buzzard. The one in London was moved and combined with the one at Leighton Buzzard. It was never used for its intended purpose but merely acted as the front end to incoming junction calls at Leighton Buzzard and directing them to either the TXE1 or one of the three TXE2 exchanges, which was decided by the first dialled digit. The TXE6 went into service on the night of 18 August 1971 and proved very reliable until withdrawn from service in 1977, when a TXE 4 exchange took over from the TXE 1 and three TXE2 exchanges. Exchange description The TXE6 consisted of two parts: a unit for receiving digits at 10 pulses per second (p.p.s.), followed by a two-stage cross-point-switch. The 10 p.p.s. unit was the interface, converting information from dialled pulses, in Strowger form, to fast parallel signal conditions for the reed group-selector registers. The 10 p.p.s. unit was equipped with four controls, and on each there were 96 access circuits, making a total input of 384 junctions. The intermediate switching unit also had four controls, each of which was divided into two parts. Each part controlled a switching unit of 48 inlets and 200 outlets arranged over 10 levels. This gave a total of 1,600 outlets over the ten levels or 160 trunks per level. The outlets were graded over the four controls. A feature of the TXE6 unit was that two equipment levels could be combined to give an availability of 40 trunks from any one level. This facility was used at Leighton Buzzard. Timeline of TXE exchanges References The Leighton Buzzard Electronic Telephone Exchange - S. H. Sheppard IPOEE Journal January - March 1967. The Leighton Buzzard Electronic Exchange - T. J. Shiplee IPOEE Journal April - June 1972. Electronic Exchanges: The Steps Leading to TXE4 - C. A. May IPOEE Journal October - December 1972 TXE4 Electronic Exchange System Part 1 - J. V. Goodman, J. L. Phillips IPOEE Journal - January - March 1976 TXE4 Electronic Exchange System Part 2 - J. L. Phillips, M. T. Rowe IPOEE Journal - July - September 1976 The reed-electronic exchange (REX) system at Leighton Buzzard