The UAX Project

I am presuming that this was the code given to the exchange which was installed on the first floor of Ramsey Post Office in Cambridgeshire, and replaced a CBS manual at 1pm on Monday October 24 1921. Ramsey is situated approximately 13 miles from Peterborough, which at the time had two manual exchanges, a local exchange and a trunk exchange. Ramsey had four junctions to Peterborough which all terminated on one position of the trunk exchange, this position being fitted with a dial and four dialing keys, in association with each junction. This was done as most of the trunk calls originated for subs who were at exchanges beyond Peterborough, and couldn’t be completed on demand. As the trunk exchange closed at 7pm a key was provided to switch the junctions to Peterborough local exchange, where a similar position was provided. . To call Peterborough exchange from Ramsey 01 was dialed.

The other junction on Ramsey exchange was to Warboys manual exchange (which was in the unit fee area of Ramsey), which made Warboys the first tandem exchange provided via a VAX. To call Warboys, from Ramsey 00 was dialed. To get to the Peterborough operator from Warboys, 01 was dialed; in the reverse direction 00 was dialed.

The exchange itself was manufactured by Siemens Brothers and ran off two 40-volt batteries, which were arranged so that one battery supplied the exchange for 48 hours, when the second battery took over, again for 48 hours. When the battery was first out of service it was arranged to be automatically charged via a petrol engined generator set. When charging was completed, the charging and engine stopped, the whole charging cycle being controlled via a clock mechanism.

The ultimate capacity of the exchange was 80 subs lines, numbered in the range 20 to 99. There was an allowance for 10 junctions, and twelve simultaneous connections. Each subs line and junction was associated with a pre-selector, which hunted for a free connecting circuit. Ramsey was initially equipped with 8 connecting circuits, 40 subs lines, and eight junctions. Fifty pre-selectors being fitted at the outset. The selectors were of pre-2000 type. The exchange was also the first to be equipped with Dialling tone, ringing signal (although this wasn’t received when you were calling from a junction), engaged tone, and NU tone. No provision was made for party-lines, coin-box lines, PBX and auxiliary lines, or for trunk offering.

Metering took place on every call, when the called sub answered, but calls out on one of the junctions were not metered, and had to be ticketed at the manual exchange. The exchange worked on first party release, ie the call cleared down when either sub replaced his receiver. There was not provision for the operator to hold the connection.

If a fault developed, or the sub left his handset off hook, the exchange released the seized switch, and locked the line circuit out of use until the receiver was replaced or the fault cleared. Faulty common equipment was notified to the trunk exchange telephonist at Peterborough by intermittently actuating the indicator on the number four trunk, this signal giving an engaged test when the trunk was free, and waited for the trunk to become free before operating. A fault test number was also provided (on number 19), and if everything was in order NU tone was received, faults giving engaged tone. This number was called three times a day in addition to the 8 am trunk test.

Ramsey exchange survived for some considerable time, I don’t have the actual date, but certainly before January 1939. The equipment gave excellent service throughout it life, with few failures, and complaints from subs.