Satellites, mobiles, dependants, reliefs and other things...

A recent train journey that passed through Newbury revived old memories. Newbury was one of those towns which well into the 1970s retained a very odd telephone system. Odd? Well, yes...

For Newbury had an automatic exchange, yet not a single Newbury subscriber was connected to it. Anyone who had a phone in Newbury was connected to a manual exchange, quite a large one, which was not due for renewal for quite a while [a few subscriber in Newbury did in fact have dial telephones, on the Avonbank relief exchange]. On the other hand, all the surrounding villages and towns had auto exchanges (UAXs) of their own and these were interconnected by a tandem automatic exchange in Newbury.

Dialling 9 from any of these dependent exchanges would get you Newbury but there were no auto numbers in Newbury except 999, so all you could dial through Newbury was to other UAXs in the Newbury group plus junction circuits to adjacent large (automatic) exchanges (such as Reading). There was no subscriber trunk dialling for these subscribers in those days and all such calls were had by dialling 0 for the Newbury operator.

Eventually of course Newbury itself went automatic and this curiosity then ceased. I can't think of any similar situations but no doubt some of our readers can. Let's hear from you!

The conversion from manual to automatic could be a complex process and the mechanics of the transfer are discussed in volume 2 of Atkinson's book Telephony. In some places the payphones were converted before normal subscribers, in others the order was reversed. Another curiosity of the 1970s was the case of manual exchanges that were fully exploited and for which automatic 'overflow' exchanges were provided. An example was West Forest (auto) at Wokingham (manual), again in Berkshire. Overflow or relief exchanges could also be manuals relieving manuals – e.g. Heathfield Tower relieving Heathfield (Sussex) or auto relieving auto – e.g. Chaucer relieving Canterbury and Fordwich relieving Sturry, all in Kent.

In the latter case Sturry was a UAX and the only spare level there was level 1, so most unusually Sturry subscribers dialled 1 for Fordwich. What Fordwich subs got if they dialled 9 is not known – probably Canterbury (three miles away) rather than Sturry (one mile away). To reach Sturry subs they probably had to dial into Canterbury and then out again to Sturry. Note that Fordwich was an identifiable geographic name; it was more common to give relief exchanges 'vague' names like Chaucer and West Forest (in the Bedford telephone area they chose names of birds for these relief exchanges).

The names chosen for temporary exchanges would repay study in fact, even though many did not last long. In fact this fact enabled 'good' names to be re-used at a different location. I believe both West Forest (Berkshire) and Fitzroy (London) had two lives; Franklin (London) had three. Again no doubt readers can supply more names. CORinthian was the name given to the temporary exchange provided at Wembley for the 1948 Olympic games and then you had permanent arrangements for seasonal exchanges such as Airshow (Farnborough, Hants.) and Royal Show (Kenilworth).

In some cases a new exchange nominally served a close but separated town or suburb, but in fact the served areas overlapped. Kearsney (auto) served part of Dover (manual) and the heavily used payphones at Dover Marine station were connected to Kearsney auto exchange in order to relieve pressure on the Dover operators. And if my memory doesn't fail me, when Wallingford UAX7 (a rare survivor) became full, new subscribers were connected to nearby Crowmarsh Gifford.

Even the railways had relief exchanges of a kind – both Waterloo and Victoria (London) had a 'UAX' (so-called) of their own, serving telephones on the station platforms and other operational locations which were not considered worthy of having extensions off the administration PABX. At Bristol, when capacity on the PBX was all used up in the 1970s a new exchange called Bristol Satellite was opened. To telecomms people no doubt this all made sense but I wonder how the average railwayman reacted to names like UAX and Satellite.

Finally, to close the article (and use up the rest of the page!), here are a few more of the attractive but short-lived names of overflow exchanges.

All the following were in use in Kent at times during the 1960s and 1970s

  • Bearsted Green (relief in the Maidstone group)
  • Beltring (Paddock Wood relief)
  • Berengrave (Rainham relief)
  • Broadstairs Sands (Thanet relief)
  • Canon Court (Wateringbury relief)
  • Chaucer (Canterbury relief, located on the north-east corner at the junction of Stoiur Street and Beer Cart Lane)
  • Cherryhill (Newington relief)
  • Claypits (Boughton relief)
  • Coldrum Stones (Fairseat relief)
  • Downs Cross (relief in the Maidstone group)
  • Dymchurch Wall (believed relief)
  • Fordwich (Sturry relief)
  • Foxpits (Hunton relief)
  • Franksbridge (Headcorn relief)
  • Gateway (Dover relief)
  • Grain (believed to be a mobile relief exchange)
  • Great Stour (Chartham relief)
  • Greenstreet (Teynham relief)
  • Harty Ferry (Isle of Sheppey)
  • Hillfort (Borough Green relief)
  • Honey Hill (Blean relief)
  • Hopfield (Hildenborough relief)
  • Invicta (relief in the Maidstone group)
  • Loose Valley (Maidstone relief)
  • Madison (Maidstone relief, manual)
  • Nailbourne (relief for either Littlebourne or possibly Barham)
  • Orchard Hill (relief in the Hawkhurst group)
  • Pilgrims Way (Lenham relief)
  • Ragstone (Aldington relief)
  • St. George's (Sandwich relief)
  • St. Werburgh (relief in the Medway group)
  • Saxon Marsh (relief in the Thanet group)
  • Shamwell (relief in the Medway group)
  • Shirley Moor (Woodchurch relief)
  • Shurland (Sittingbourne relief?)
  • Snodland Common (Snodland relief)
  • Stourvale (Wye or Ashford relief?)
  • Townhill (West Malling relief)
  • Warren (Crowborough relief)
  • Woden Mill (relief in the Dover group)
  • Wormshill (may have been a relief)
  • Yeoman's Grange (Cranbrook relief)

Here are a few from the Midlands in the 1970s and 1980s:

  • Avon Valley (relief for Pershore)
  • Avonside (relief for Stratford-upon-Avon)
  • Beckett, Kingsthorpe and Weston Favell (Northampton relief)
  • Banner Lane, Bondgate, Chamberlaine, Great Heath and Quinton Pool (Coventry reliefs)
  • Broadwater (Towcester relief)
  • Borough Hill (Daventry relief)
  • Chelveston Base (relief for Raunds)
  • Church End (relief in the Coventry Telephone Area)
  • Churchfields (relief for Bromsgrove)
  • Foregate (relief for Worcester, opened and closed more than once in the 1970s)
  • Goldcrest (Newport Pagnell relief)
  • Ipsley (relief for Redditch)
  • Isebrook (Burton Latimer relief)
  • Meadowside (relief for Stratford-upon-Avon)
  • Pavilion (Rugby relief)
  • Pineham (Milton Keynes relief)
  • Rainsbrook (relief in the Rugby group)
  • Redwells, Spinney, Swanspool and Threeshires (Wellingborough relief)
  • Salwarp (relief for Droitwich late 1960s/early 1970s)
  • Skinners Hill (Rushden relief)
  • Southcrest (relief for Redditch 1980/81)
  • Stonebow (overflow for Peopleton, in Stonebow Road)
  • Stowehill and Weedon Beck (Weedon reliefs)
  • Valiant (relief for Gaydon)
  • Wellesbourne Park (relief)
  • Yardley Gobion (relief)

And some others, not in the Midlands

  • Avonbank (relief for Newbury, open between 1st April 1973 and 6th October 1976)
  • Markyate Park (relief for Markyate)
  • Tanlan (relief for Mostyn)

Amendments and additions welcomed!

From John Smith, Shottery:

I found your article on relief exchanges (Journal 25) of great interest. You mention Avonside; this was a mobile exchange relieving Stratford on Avon exchange. It was sited, as its name implies, alongside the River Avon in a meadow. There were two other mobiles; the other was named MeadowsideWellesbourne Park was a relief exchange in the village of Wellesbourne, near Warwick. From Stratford you dialled 83 for Wellesbourne and 72 for Wellesbourne Park.

Another village near Warwick had a relief mobile; this was Kineton and its relief was named Valiant in tribute to the local RAF V-bomber station at Gaydon, which had a squadron of valiant bombers. Gaydon airfield later became a motor vehicle manufacturers’ test track and subsequently the Gaydon motor museum.


The Mobile Non-Director, Reliefs and Hypotheticals saga is interesting. I attach a list of ND(m) names as at 1967, which I hope will be of interest.

Abingdon was certainly still manual in the early 70s, and rumour has it that there were several caravans in the yard, serving as a Tandem for incoming STD to the 0235 number group. Didcot had already got outgoing STD, presumably as a dependant charge group on Oxford - there was a route in the reverse direction on level 939. Incoming STD to Didcot and its neighbours seems to have been via the mobile tandem at Abingdon. Didcot itself acquired an ND(m) to expand its numbering range into 5XXX at about the same time.

Wallingford, just down the road from Didcot, was a UAX7. Fascinating system! The transmission bridge and ring-trip circuit were in the first selector, with the final pulsed over one wire, returning ‘state of called line’ indications over the other. If the line was engaged, the final was released. Fine until you had an early choice faulty final that thought  every line was engaged, and each time was released to cause more trouble!

The system absorbed the initial 2 or 3 of a four-digit number, setting up Wiper Switching conditions accordingly. The next digit stepped the first again, selecting a final, and passing forward a signal to indicate 2XXX or 3XXX, like the UAX 14 - except that pre-2000 digit absorption could be achieved in the inter-train pause, but 2000-type switches like the U14 could easily be caught out with the second digit during release.

When every level apart from 9  was allocated to finals, the UAX7 was exhausted. Undeterred, the PO people of the day wheeled up several caravans to Wallingford, parked them in a nearby public car park, took out a pane of glass in the exchange for cabling purposes, and created a rather nice solution to the problem. The caravans were called ‘Crowmarsh’ (the village over the river from Wallingford). 26XX and 36XX numbers were changed to Crowmarsh, freeing level 6 on the UAX7 for a route to the ND(m) exchange. What I have been unable to find out is whether there was a linked numbering scheme between the two exchanges. Certainly the AGS 105 first selector diagram was modified at about the right time to allow for incoming 2nd selectors to be created which ‘thought’ they had already absorbed either a 2 or a 3 on seizure. That digit, of course would have been used up in the caravan to seize the junction to the UAX7. Maybe another reader will know if this was for Wallingford/Crowmarsh or some other site.

After replacement by TXK1, bits of Wallingford and Wolverton UAX7s were used to form an intercom system for a missionary society in South London for some years, but sadly that equipment has now been lost. However, I understand Llangollen (not Pentre Ynfyntyn Ebrill) UAX7 has been preserved.

I also have an intercom system in my old school, comprising a ‘Double UAX12’ extended with a couple of UAX 13  racks. I will write separately about that in due course.

Editor’s note: Thanks for this excellent listing; I must confess that Wallingford, with the unique ringing tone which UAX7s had, was one of my favourite exchanges! If I am not mistaken (and I often am), we have Bovingdon UAX7 in the Telecommunications Trust collection at Wolverton, just waiting for a solid brick building to be built around it and a weekend or two for Phil Goodwin and his team to re-erect it.


ND(m) unless otherwise noted


                                                Approx. size

  • Fancott, Bedford Area               250
  • Linslade, Bedford Area               500
  • Westoning, Bedford Area               200
  • Abingdon, Oxford Area                 700
  • Long Hanborough, Oxford Area     20
  • Tylers Green, Oxford Area            50
  • Whiteleaf, Oxford Area                 500            (MAX13)
  • Winslow, Oxford Area                 600
  • Farmland, Southend Area            250
  • Fryerning, Southend Area             150
  • Great Oxney, Southend Area           100
  • Thundersley, Southend Area         1,500
  • Green Lane, Coventry Area            200
  • Nene, Peterborough Area                 20            (MAX12)
  • Arboretum, West Mids Area            200
  • Avon Valley, West Mids Area     150
  • Danes Court, West Mids Area 150
  • Landywood, West Mids Area                 90            (MAX12)
  • St. Chad, West Mids Area                    350
  • Severn Valley, West Mids Area       90            (MAX12)
  • Wyrely Bank, West Mids Area     350
  • South Humberside, Lincoln Area            150            (MAX13)
  • Richill, Belfast Area                             200   (MAX13)
  • Greenbrook, Blackburn Area            550
  • Gosforth, Lancaster Area            150           (MAX13)
  • Great Sankey, Liverpool Area          100
  • Argosy, Liverpool Area           200             (in Director Area!)
  • Tawd Vale, Liverpool Area            550
  • Green Hills, Manchester Area    400             (LNS with Macclesfield)
  • Boundary Park, Manchester Area     550   (in Director Area!)
  • Ladysmith, Manchester Area            300             (in Director Area!)
  • Aviemore, Aberdeen Area           200            (MAX13)
  • Dalgetty Bay, Edinburgh Area              50
  • Livingstone, Edinburgh Area                        50
  • Loanburn, Edinburgh Area                      150
  • Newbattle, Edinburgh Area            100
  • Bonnyton Moor, Glasgow Area     100            (MAX13)
  • Allison Green, Scotland West Area     100            (MAX13)
  • Ash Grove, Scotland West Area     300
  • Summerfield, Scotland West Area     250            (satellite on Ayr)
  • Bellhaven, Scotland West Area     100
  • Crosshill, Scotland West Area                 90            (MAX12)
  • Cruachan, Scotland West Area       25            (MAX12)
  • Garrion, Scotland West Area                 50            (MAX12)
  • Glencairn, Scotland West Area     350
  • Seagate, Scotland West Area                300
  • Seadown, Brighton Area               100
  • Southcliff, Brighton Area               600
  • Broadstairs Sands, Canterbury Area     200
  • Loose Valley, Canterbury Area     25
  • Shamwell, Canterbury Area                 400
  • Shurland, Canterbury Area                 250
  • Townhill, Canterbury Area                 350
  • Church Crookham, Guildford Area            100
  • Cricket Hill, Guildford Area            400
  • Lucks Green, Guildford Area             400
  • Headland, Portsmouth Area                400
  • Roman Way, Portsmouth Area     400
  • Rosewood, Portsmouth Area                 300
  • Burchetts Green, Reading Area     150
  • Iver Heath, Reading Area               200
  • Loddonvale, Reading Area               400
  • Mortimer, Reading Area               450
  • Orchardgrove, Reading Area               700
  • Chalvey Park, Reading Area               700             (nameless satellite on Slough)
  • West Forest, Reading Area             1400
  • Uckfield, Tunbridge Wells Area            250
  • Warren, Tunbridge Wells Area            450
  • Oldbury, Bristol Area            150
  • Merryfield, Taunton Area     70      (MAX12 Relief for Martock U14)
  • Spon Green, Chester Area                100
  • Angle, Swansea Area                         100             (MAX13)
  • LNS = linked numbering scheme
  • MAX=Mobile Automatic Exchange
  • nameless = exchange name used for operational purposes, although
  • subscriber numbers used the name of the main exchange
  • ND(m)= non-director, mobile


From Simon Fleming, Horley:

As a minor aside to Paul Ebling's list of mobile exchanges, Chalvey Park was mentioned by name in the local calls section of the 1968 London STD dialling Code booklet (one had to dial 100 for it through the Operator), so the remark "nameless satellite of Slough" might not be correct. Uckfield itself was a manual exchange in the late 60s, but there may have been a satellite in a differing numbering range (possibly 3xxx) from the manual numbers. Warren was a satellite of the then manual Crowborough exchange, and Lucks Green was a satellite of the manual Cranleigh exchange; Town Hill subsequently became a part of West Malling exchange when the latter was replaced by a more extensive installation.



Spotted in the January 1939 issue of the German magazine TFT (Telecomms Technology): In England the development of mobile communication facilities began in 1935 with the introduction of mobile post offices; now the first mobile telephone exchange is ready for trial implementation in North Weald, Essex.



The December 1994 issue of Post Horn, the magazine of the Post Office Vehicle Club, reports: "After the account of the mobile telephone exchange trailer at the Milton Keynes Museum in the June issue, Ron Doig wrote with details of five examples lined up in a yard at Ardrossan, Ayrshire, where Clyde Coast Motor Services keep their buses. The occasion was an Omnibus Society visit, on 11th June, but the camera was diverted from the buses to the trailers which are presumably used for storage. One is dark blue with BT logo, while the other four are still green, one still carrying the GPO emblem and POST OFFICE TELEPHONES lettering.  Serials are 71 830 0023/98, 72 830 0051/74 and one identified only by its unit number, MNDX No. 318."

And there's more! The January issue reports that resident at the Avoncroft Open Air Museum (Bromsgrove, Worcs.) is green-liveried mobile telephone exchange MTX 71 830 0030. Yet another is being used as a sales booth by a railway preservation society at the Nottingham Heritage Centre, Ruddington, near Nottingham. Another is in use at Northiam station on the preserved Kent & East Sussex Railway, where it houses a working exchange serving the railway.


From Mid-Hants Telecomms dept, the Railway Station, Alresford:

A couple of comments regarding THJ number 25, firstly on page 7 it states this railway uses PAX equipment, this is incorrect, we have no exchanges of this type in service although all four of the exchanges in use employ Strowger equipment. On page 21 you list mobile exchanges, you may be interested in details of mobile exchange vans on this railway.

  • 1          66-830-3435
  • 2          ??-??-???                   MNDX 105      also on side ?T 13443
  • 3          72-830-0106             MXE C 5
  • 4          ??-??-????                 MXE LS 53
  • 5          73-830-0111             MXE LS 34
  • 6          3-830-0044               MXE C 23
  • 7          3-830-0046               MXE LS 41
  • 8          3-830-0096               

 Numbers 3 to 7 are mobile TXE2 vans – MXE (approx. 30ft long), one control van (C) and one line switching van (LS) made a 1000-line exchange (975 lines to be precise). A second LS could be added to double the capacity, the control van being equipped at the start for 2000 lines. The control van comprised  the common equipment, registers etc, power plant,  -50volt and +50volt standby batteries plus work bench. In the line switching van were the subs line circuits, switching network, supervisory relay sets (junction relay sets) and the IDF/MDF. Van number 8 is similar to the picture on page 21 and contained telegraph equipment on 56 and 62 type racks plus a Teleprinter 15. Whatever this van was intended for is not known but one can speculate; on inspection of the MDF it is  apparent no jumpers had ever been run on it.  Vans 1 and 2 contained Strowger equipment. All vans have been stripped out and are used for storage by different departments on the railway, a few TXE2 parts remain.

Collated from articles originally published in Telecom Heritage, the journal of the Telecomms Heritage Group.



  • John Chenery's survey of mobile exchanges\~fyneview\light.straw\mobile1.html


  • Martin Loach's preserved mobile exchange\~fyneview\light.straw\mndx341.html


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