CT2 - ZonePhone

Nigel Linge on CT2 at 30 year celebration

The first digital cordless phone you could buy in the UK was based on the CT2 standard.

I have some Ferranti Zonephone Base Stations and Handsets from around 1990, they were of course not as famous as "Rabbit"

The base stations are not the type you would have in your home, but the type for public use

They look very much like the defence equipment Ferranti may also have been making

They consisted of a "Communications Module" PCB, that has the telephone line interface, DTMF, Modem and Static memory.

This PCB is marked Communication Control Ltd

The static memory held amongst other things all the serial numbers of the CT2  handsets that had subscribed to the public service

ZonePhone Call Management PCB

A CT2 radio box containing two PCBs

CT2 Radio

CT2 Radio Box - RF board

CT2 Radio Box - Micro Board
 "Communications Module" PCB communicates with the CT2 radio box via a serial link.
The "Communications Module" PCB can even cut the power to the CT2 radio box

There was also a Mains power supply and Back up lead acid battery

Later Versions (The 4 on the top row), were lighter in colour and slightly less Military having paper labelling and cost reduced boxes

The boxes shown above were installed in another metal box which had a radome on the top, and a mains socket and BT phone socket inside.

Two Aerials were protected inside the radome.

The early models of the Inner metal box had a port for "infill"

But the all the CT radio boxes I have don't have an connection for this (infill).

It looks like each of the base stations can cooperate perhaps with things like channel allocation, by connecting in a RS485 Daisy Chain, via the SYNC connections.

 0130  0130  0130  0130
 0317 0317 0317 0317
 0485  0485  0485  0485
 1007  1007  1007  1007
 2027 2027 2027 2027
 6044 6044 6044 6044
 8007 8007 8007 8007

The Science Museum, have one of the domestic Zonephone bases here...

Originally published in IEE Review, May 1989 (Volume 35, Issue 5)

Payphone link

"...Phonepoint. Owned and operated by a consortium including STC, British Telecom, Telecom France and US-based Nynex, Phonepoint expects to establish its first telepoints this Summer. As well as the typical telepoint locations identified by Phonezone, Phonepoint may possibly be able to take advantage of the 80 000-location network of BT callboxes, which would provide prime sites for telepoints around the UK. Indeed, the telepoint development raises the question of whether these traditional callboxes have any future."