Bunkers original telecommunication equipment brought back to life
Case MSX Message Switch The Case MSX was installed at all main bunkers it linked to its neighbour using private lines from BT, to make best use of these lines S+DX equipment was added to allow speech and telegraph to use one circuit. Often the land lines were backed up by radio, a relay set AD6886A was used to send via the radio systems. The MSX network allowed an operator to send a message to any other terminal or printer on the Home Office network, the message format was very strict. Smaller regional offices like council HQ’s and Main Police Stations had a smaller system called Autex An MSX was installed here at QQGU, its location was Room 5B with the Terminals and Printers in the message booths next door in Room 5A, the whole area would be called COMCEN there are still blocks on the far wall marked MSX, just inside the door is a block marked Teleprinter’s which probably served QQGU during the transition from Tape Relay to automatic systems.
 
Autex Telex Manager Regional and District offices like council HQ’s and Main Police Stations had a system called Autex to connect ot the Home Office MSX network, The Autex boxes came in two configurations depending on how large the facility was and if backup was required. The Autex 100 District had One Terminal, Two Printers and Two Links to the MSX network; while the larger 1600/100 system had Two Terminals, Three Printers and Four Links, the 100 could be switched in should the 1600 fail. These devices were built and installed by Chernikeeff Telecommunications Ltd. The Autex on display here is a 1600/100, it is fully functional and will be connected to the MSX in the future to recreate the Home Office network as it was. The Autex used Siemens Printers and Zentec Terminals, the system password was found hand written in an Operators Manual, without that the system would not have been brought back to life, thank goodness security was tight then too!
 
Cipher Terminal The Cipher Terminal was used on the MSX network for input of data for transmission to remote printers. This Cipher Terminal typical of those found in Home Office and ROC bunkers, they can be seen in many of the photographs around QQGU. This one and others will be connected to the MSX when it is restored. This machine is one used here at QQGU
 
Triple Head Tape Sender These devices are normally single however this special sender allows an operator to send 3 tapes at once using one motor, it is possible to lay a tape across all three heads to sent the same tape to multiple destinations. There was a PJF for patching to different bunkers and the MAR contains two broadcast units, these had a switchboard attached. This machine is one used here at QQGU
 
TDMS Telegraph Distortion Measuring Set is used to set up and test telegraph lines and teleprinter devices. The TDMS can send messages and measure the distortion of teleprinter traffic, the distortion is shown on the screen by displaying a ring with two blips showing the sent and received signal. Ideally the two blips should be aligned. This is an older type there are many different types but most have the same basic functions, more modern versions have easier to use and more comprehensive displays. The one seen in the rack area has recently been used to set up S+DX units that are used in our link between this room and the Comcen, it can also be patched into the circuit to send messages to either teleprinter.
 
Teleprinter 7 Teleprinter’s like this were widely used in commercial service both on Private Circuits and the Public Telex Network. Manufactured by Creed Ltd these machines provided reliable service for many years. There were many variants of this type depending on the customers requirement. Everything is adjustable and required regular maintenance and oiling, Tape Relay Centres typical had two of these for printing messages for the bunker both incoming and outgoing. This teleprinter is a 7BN3 and has a paper tape punch and reader, it is similar to those used in the Tape Relay Centre for printing incoming messages from paper tapes received on the re-perforators and for making messages leaving this bunker here at QQGU
 
  Bunker Blogs

First Contact

After ages of searching the web and bugging old contacts at BT I started mailing just about anyone who may have or know where I would be able to acquire an Autex Telex Manager.
These boxes were used at regional and local government locations and connected back into the MSX network which comprised a couple of racks full of Case equipment. The system was an early e-mail system and used during the cold war, it was similar to the public telex network but faster and requiring strict message formatting. The system had an early form of QoS (quality of service) now in regular use by the switches and routers that make up the internet. Messages could be typed in and sent to their destinations or multiple destinations if needed, the destinations were usually line printers or special telex machines developed by Trend Communications. The Autex boxes came in two types, the 1600 and 100 in a cabinet with a change over switch and a 100 in a small desktop enclosure, these used SCVF (Single Channel Voice Frequency) to connect to the MSX or other Autex sites.
My interest in obtaining one of these is to include the Autex setup in my private museum; I like to do restorations but am more than fanatical about making stuff work so condition was not really important. My museum has lots of communications ranging from a reproduction of a Lancaster’s radio position to a fully working WB1400 early warning system. Space is limited now as the museum has grown recently although the barn it is in is of a reasonable size.
So the e-mail list was large and diverse, I saw some references on Subterranea Britannica of Autex boxes and mailed all the councils, along with that I hit every museum I could think of. Of all the mails I received a few replies but most interesting was a reply from James at the Scotland Secret Bunker who told me of a few large containers he know of. So a family trip was in order, we had a couple of days in Fife which turned out to be a really great place to visit then a trip to the secret bunker. To keep this short I found exactly what I was after and even better it turned out to be the 1600 and 100 unit, I also found a monitor and correct keyboard but forgot the printer in all the excitement. I did a deal with James that I would come back within a couple of months and work at the bunker for a week to see what exhibits we could bring to life to make the museum even more interesting. During the search for the Autex units we found 6 Case MSX racks, they looked complete, I didn’t think any of these still existed, along with these were more Autex boxes, Cipher Terminals, and a load of other very interesting bits of cold war communications history, coming back to work for a week becomes even more appealing!
Once home I did a quick safety check and applied power to the units, shortly after doing there was a loud band and tons of smoke, only to be expected after such a long time in storage even though the storage was dry. The 1600 blew a capacitor in the power supply which is fairly typical, anyhow I have replaced all of them to be sure, now the 1600 was working and I had a command prompt on the screen. While the 1600 was in bits I removed the backup battery which probably caused the caps to blow, it is exactly the same type used in motorised garden toys so I will replace it soon. The 100 did not run I traced this problem to a leaking backup battery; the leakage had eroded 3 fairly small printed circuit board tracks so I had to clean and hardwire the breaks. After that and with a new battery the 100 also came online. Now to the command line, I managed to get a manual copied from a friend whom I made during the email list; trouble is to use any of the useful commands you need a PASSWORD!!! Without it I made some basic tests by hooking up the SCVF lines to a message generator and was able to see journal prints (on a terminal program running on a PC as I forgot the printer). So on goes the hunt for the password, it turns out a manager I worked for several years back at Bay Networks worked on these for Chernikeeff, he may come up with the password yet?

Day 1,

I arranged a week out of my painfully busy work schedule to visit James at the bunker and repay him for the Autex boxes he kindly let me have.
James simply told me to treat the place as my own and just do my thing which is perfect, the only trouble I had on the first day was a complete lack of focus, there was so much to work out and tons of old equipment dating back to the 1960’s it was hard to see what was possible in the short time or 1 week. Mainly I wanted to get a couple of teleprinters working so messages could be sent from one to the other, fairly simple but I found so many other interesting items I began to work out a way to use more of the vintage equipment.
The bunker is a museum and has been set put for that purpose, looking through all the paperwork and equipment in the BT room it became clear that a tape relay centre (similar to one I saw a Bawbrgh in Norfolk when I was an apprentice at BT) once existed in the next room. This was fascinating then and even more now; I didn’t see the equipment associated to the centre back then just the banks of re-perforaters and tape senders.
This is now a cinema, there are some cables and heavy duty conduits heading that way. An MAR rack is still in the BT room, still fully wired, it has many relay sets filters and 2 broadcast units. Power for the rack and for the now removed tape relay centre is still in place along the back wall of the BT room. I followed some of the conduits under the floor, there is plenty of room to crawl around, some RAF electrician had written his name just under the trap door “Dougie Bemdell 1964 GPO Sparks” I am sure there are things left under there, I saw an old cigarette pack, how about having a smoke under all that wood! In the documentation there is a hand written drawing of the tape relay centre, it was quite comprehensive, 4x Cabinet Telegraph 2A each containing 3x Printing Re-Perforators Creed 85B/M’s, 4x Tripple Headed Tape Transmitters Auto Transmitter 3B, 2x Teleprinter 7B, Special Key Switching and a PJF. I reckon it would look something today had it still been in place, this was message routing by humans rather than electronic switching, all the machines received messages from distant bunkers and had the capability to resend (relay) the messages to others and to send messages of their own. While looking around for suitable machines to get working I found a Cabinet Telegraph 2A that I believe came from the tape relay centre, it is at the back of the ROC display, along with that in the Comcen I found a printing re-perforator and a 3 headed tape transmitter, too much of a co-incidence, they must be from the bunker, I will put the reperf in the rack later in the week after I get it working, the rack needs a good clean out as the sound proofing has turned to powder. It would be great to re-create the tape relay centre, getting more racks may be a challenge but this really is a piece of history and the hard to get (impossible I think) MAR rack is already in place with all of its cabling and much of the jumpering to associated transmission and S+DX gear. I decided to apply some power to MAR and sure enough valves lit up in the broadcast units and relays chattered, this can defiantly be made to work again.
Back to reality, there are loads of BT Cheetah teleprinters in the bunker, I am not keen on them to be honest, the power units run so hot and I remember the BT maintenance man in the East Anglia area Mick Dale forever changing them. After being out of service I expected a few of them to smoke and was not disappointed, I got one out of three to work reliably and am leaving it at that until I return with a variac to wind them up gently. A rack of unit telegraph 55’s is in the BT room, it is an addition but a useful one as most of the Cheetahs are SCVF and need converting if we want to use them with other equipment in the Bunker, while not exactly a true cold war device they have the correct era and can be very useful to prepare messages and send and receive paper tape. In the store I have located several Trend 610 Teleprinters, these are exactly right and would have been connected directly to the MSX, along with these are Cipher terminals these also connect to the MSX. I will set up the MSX in the BT room for now, the original location I believe is at the far end of room 5A which now has the switchboard consoles. Room 5A is mentioned in several documents as being the teleprinter room, next door where there are now Teleprinter 15’s was a row of phone (message) booths, I am not sure but the booths may have had a Cipher terminal or Trend 610, more digging around will no doubt clear this up. All this makes me wonder about the location of the telephone switchboards; that is for another trip, telegraph is my main interest this time round.
In Room 5A there are a couple of more relics from the tape relay centre and I am in no doubt they are from here, 2 floor standing boards with small slots cut in perspex on top are for storing paper tape messages received, they are labelled as to what needs to be done with each message, i.e. archive. The paper tape used in tape relay centres use the chad-less system, the machine that punches the tape is a real piece of engineering, it is like a teleprinter 7 but rather than a platern (Cork or rubber roll for the paper to rest on while printing) and a roll of paper the print head and tape punch are combined, as the tape is punched the print head prints the received characters onto the paper tape. The punch leaves the chad (waste from the punched hole) attached, no need to empty chad all the time, considering the traffic it is a big bonus, also chad has a habit of getting everywhere.
So to get some focus I decided to re-cable a telegraph power unit and get a TDMS (telegraph distortion measuring set) working so I can send messages to the machines to make sure they are working along with aligning the S+DX units and if possible testing the MCVF system I found in a rack beside the amplifiers and transmission equipment. There were 2 TSMS’s on a display table, the first was OK but the display was a bit erratic, also the message generator was faulty, the second was much better, I soon had the first Cheetah displaying an printing messages in the BT room.
I was looking around for some print ribbons and in the Comcen I just noticed a Chernikeeff folder, on opening it I recognised it as the Autex book my contact had sent by e-mail, this one was different though, some thoughtful person had added comments and additional commands including….. The password!!!! Now I need to get an Autex into the BT room to try it out, going home is too far.
In the Comcen there are a load of teleprinter 15’s big ugly grey typewriter based devices, although they work well and the print is very clear. I decided that I would get one working, I only found one complete unit telegraph, this has the power supply, it is a commercial one with a dial but it will do until I can fix one of the other 2 PW (private wire) units. Each machine has a different fault so I picked the easiest option; this one has a faulty tape transmitter that will fix easily later. With this running in local record I decide to end the day and go get some food and sleep….

Day 2,

Day two, I have had a lot of time to digest all what I saw on the first day, focus is much easier, especially with the working 15 ready to connect, first off I found a block that was used for the message booths and picked a spare pair of wires, back at the BT room I found the teleprinters signal. My plan after a night’s sleep is to get a message from the TDMS over 2 S+DX units and out to the teleprinter. The S+DX units are big old panel mounted types there are 16 here still wired up and with their circuit numbers and destinations written on the front, again I remember seeing these at Bawburgh, one of my old BT colleges Trevor Harroven replaced them with a chassis mounted RFL systems device (there is one here too) the big units were then scrapped and I didn’t get any of them for my collection. Out of all the units in the 2 racks I found an A and B type they have to be in pairs for instance an A at Aberdeen and a B at Edinburgh. What they do is to allow a duplex telegraph circuit and voice (switchboard) line occupies the same private circuit between 2 bunkers. I used the TDMS to set the bias in each direction, this clears up any distortion, I just patched them together on the PJF which is part of the same rack. Now with everything connected I can send a QBF (Quick Brown Fox) message from the BT room over S+DX (as it was) and across to a teleprinter in the Comcen. The Plan now is to hook up the Cheetah so people visiting can send messages too. Speech is to be done later.
I planned on using transmission equipment between the S+DX units but the amplifiers will need a little work as there are some nasty mains hums on the outputs of most of them. The transmission racks are awesome, I will look for a date on the tomorrow, they are really old, I saw engineers scrapping these at RAF Watton, I think some were war time. After those at Watton were scrapped I remember reading about the Colossus rebuild at Bletchley Park, they were appealing for valve bases exactly the same as used in these amplifiers. They are deep and look like Bakelite; anyhow they are good at heat resistance. I was so sad I had not been able to save a load of those amplifiers, now I am looking at 3 racks full of them again, I bet there are not many more around. Around the other side of the Amps are transformers, terminating units, equalisers, all of which I am familiar but albeit a lot older.
The S+DX and teleprinter link worked great all day, I punched loads of tape and hung it on the tape stands I the comcen, OK it is not chad-less but it is 5 unit tape with messages on it. If I can get the re-perforator going I will make some real tape relay tapes!
We moved 2 MSX racks and an Autex from storage into the BT room, they were fairly heavy but between four of us a trailer and 2 hoists we got them into position, tomorrow I will work on them, the MSX will take some effort for sure. I found the disks and al the proper Case handbooks this evening which I hope will help. I also discovered at least 2 more MSX racks 3 or more Trend 610’s and loads of Cipher terminals some with the swivel base.
The MCVF (Multi Channel Voice Frequency) system is kind of working, MCVF allows lots of telegraph circuits to share one private wire, we only have one so I had to loop it back, its alarms are clear and I can send data round the loop, I wonder if it would work over an VoIP port? I recon a couple of cheap Cisco 2611 (I love them as they pay my wages) with e-m wics and a g.711 codec would do the trick, anyone out there got an MCVF system and an internet connection?
I managed to get a Trend 610 to work too, I now need to get a load of ribbons as all those in the machines are dry and do not print well. A second and third 610 smoked so I stopped there; reckon my next visit I will be armed with a load of capacitors! I want to get the 610’s on display, if possible in place of some Cheetahs as they are more in line with what would have been used here.

Day 3,
Day three, I went to find some teleprinter ribbons for the 15’s but so far nothing, however I discovered another 80-0-80v power unit that I need for the re-perforator and an amazing test desk table. I think I once saw one at RAF Watton, it was long since disconnected even then. I think it is associated with ancient MCVF equipment, anyway it is really old. It will stay where it is for now as there is too much other stuff to do. I found 4 teleprinter record cards; I will look at the serial numbers on the machines I have to see if any tie together, the cards are for teleprinter 7’s.
The re-perforator proved a lot trickier than I first thought, on initial inspection it looked ok however after a while on the workshop bench it is clear lots more time and spare parts are needed to get it to work. First though I decided to wire up the plugs on the workshop bench (which is the old telegraph test desk) so I can have the 160v dc motor supply and 80-0-80v easily to hand, the test desk is missing its original unit telegraph and lots of the wires are cut, I did find the diagram and put it aside for a later rewire when I find the right parts. Back to the re-perf, the motor was missing its front cover and had a nasty dent to the governor. Anyway I put power on it and it didn’t move, after some DC checks I found a wire off in a small round pin plug, still no good so next I found the brushes were not making contact to the governor. After cleaning them the motor lurched in the wrong direction! After polarity checks I tried a motor off a working machine which did exactly the same, at the same time I noticed there was no manual winder on the tape punch/print head, cranking the machine by hand also showed up the punch was not operating, not even advancing, the print head was doing its thing though. I found several bent levers in the tape punch, knowing I have one spare at home that will clean up I decide to put the re-perf on the display for now. It is a shame as I would really like to leave here with something from the tape relay room up and printing chad-less tape. I am totally prepared to give up one of my own beloved re-perfs to have one working at the bunker, next time I will bring it along both for comparison and to leave should I need to.
I put the triple head tape reader, the re-perf and a 7b on the display table, on the floor below will go a Trend 610 and a Cipher Terminal to represent the old and new. I have to make a load of labels for the exhibits James can print them, and I must photocopy the priceless hand drawn drawings of the tape relay room.
I put the Cheetah in the public area and connected it via a unit telegraph 55 (It is an SCVF unit) to convert to 80-0-80, then hooked it up in place of the TDMS, now it is possible to send and receive messages between the comcen’s teleprinter 15 and the the BT room cheetah, both have paper tape punches and readers, I am not sure how we allow the public to get to the 15 yet without blocking the view into the teleprinter room, still thinking about it… Anyway it is good to know that we are using the S+DX in both directions, I put a telephone receiver across the S+DX line so visitors can listen to the sounds sent across the private wire. I noticed one S+DX unit has a carpenter relay, when I checked the bias adjustment today it was out and the pot on the front of the unit wouldn’t go any further. By the way to do this you set up the TDMS to send 1 to 1 transitions, +80 to -80 then back to +80and so on, this is fed into the first unit, the receive on the other unit is hooked back into the TDMS. On the TDMS displays you see a glowing ring with 2 dots that represent the sent and received signal, the bias adjustment is altered until these two dots are aligned on the ring. If they don’t align then the carpenter relay may be adjusted, with the panel adjusted to the centre position I removed the lid of the relay to find one locking screw was loose, easily adjusted with the main adjustment screw I fastened the lock screw and checked the other side too. Now the S+DX units are set up I will check the bias again tomorrow. The link between rooms works well I just need ot make up a diagram and instruction sheet.
So next up is the MSX, it is in a fairly bad state from initial inspection, but it is all there and we have tons of spares as one or two other cabinets are in worse condition. The MSX is built from several components, mainly there is a computer, this is a big old clunker, there is a Case DCX which is like a BT5500 mux, these were like Cisco routers in their day, and if you had Case training you could demand good pay and were in big demand in the IT industry. I decided to get power into the rack first; there are two boxes in the way before power gets to the mains strip. Anyhow I had to bypass a strange octal connector/isolator. Plugging in the DCX was like guy fawkes day, tons of smoke and a nice yellow flask of lightning, I love a bit of electricity flying around, the power unit upon removal was really dusty and looked as though it had got hot in the past, so another power unit is on the pile of repairs. I will look out another tomorrow. I have found the installation guide along with the rest of the Case books so wiring will be easy now; there is a lot of detail about operation too.
The Autex 1600 worked, it has a journal printer on prt 1 and a terminal attached to port 1 I removed the backup battery first; nothing showed up on the terminal but the led’s on the front showed power, run and clock so it looked good, I changed the serial board and the terminal burst into life, the password was spot on so I had a quick go at making a directory without much success so far, the file gets created but does not show in a listing, I can also delete and save files now which is great. The 100 didn’t power up so I removed it from the rack, on inspection it is badly corroded and may need replacing.
I decided to check out a couple more of the cheetahs in the main display, James thought it would look good to have something live there and I think so too. I was a lot more lucky this time, some of the machines were not complete so by swapping power supplies I got 3 working, 2 of the m are older 80-0-80v and one is SCVF and will need a UTG 55 to convert. I will set them up not to print so they don’t use loads of paper but the messages will show on the screen. I have to work out what the input will be, I could use a software tool written by a friend in the USA called Heavy Metal it can take an input such as a stock ticker of a file and send it to a 5 unit teleprinter (fairly cool but I only have a day and a half left) I may put a machine in the public area to send messages themselves to the screens on front of them. So the last job today was to get 3 cable pairs from the telegraph rack in the BT room to the floor where the machines are standing, I am doing this for flexibility to change how this works in the future, as luck would have it there was an old block on the wall with pairs via a DP opposite already jumpered to the MDF in cloth jumper wire. Just 3 additional jumpers on the MDF drought the pairs to the telegraph rack, I am using spare patches on the S+DX COP.

Day 4,
Day four, First thing to do is to get the display in the main operations room working, the two 80-0-80 Cheetahs seem to have good power units so I wired these back to the patch panel on the S+DX rack. I decided to use one of the 23’s to send a signal to the Cheetahs. The first 23 powered up but when the line was loaded the signalling voltage dropped to zero, I took a look at the power unit and found nothing obvious wrong. The second 23 worked fine, the 2 Cheetahs loaded the line and dropped the voltage to around 68v which is fine. I wired the 23 back to the patch panel too; this will allow me to work on different schemes in the future. So now when you press the call button on the 23 and type it wakes up the two Cheetahs and the typing appears on their screens, The 23 tape punch works so this can make a tape for visitors to take with them if they want a souvenir. The good 23 needs some mechanical maintenance, I think the carriage rail is dirty or gummed up as the print head is slow to return, I will look at it tomorrow as well as labelling everything up so I do not forget the next time I come back.
I checked out the WB1400 equipment, the original WB1401 Receiver Speech and loudspeaker are in place along with all the wiring, James confirmed it still ticked when he first came here. There is a CCP at the back of the operations room but it has no terminating unit, there may be one in storage, if not I will make one up, it will be perfect to have our own self contained system on display and working, there are several WB1400 bits around including the very useful Power Unit WB1401, this is on the wall in the canteen.
Clocks look promising too, the master clock battery shelf is long past its sell by date but the pendulum clock and power unit look perfect, this is another project for the variac, I don’t fancy throwing the mains switch, good news is there are mains sitting there ready to go!
The display in the BT Room has been altered, I have put as much of the small Tape Relay equipment as I could find on the left hand table. The telephones are now on the top shelf along with some pabx/exchange testers and associated gear. The Autex is moved to the right side table and a second printer connected. Alongside this I have put a Cipher Terminal on its proper rotating stand and the working Trend 610 Printer. The Autex manual showing the hand written password is in the display too.
I am not going to attempt any more work on the MSX until I get a variac on site, I checked the supervisor cards and all their backup batteries have leaked and corroded the circuit boards, this is a nightmare, I will try and clean them up ready for my next visit. I cannot let any more power units go up in smoke otherwise I will be changing capacitors for the rest of my life!
There are at least another 2 Autex boxes in store, they look to be in good condition, I plan on getting at least one more system working for a second display in another room. Once I work out how to enter the routing tables on my system at home I will be able to send messages between them over the SCVF links maybe even hook my system into the ones here over the internet. I think it will be a while before the MSX is up and running, by the way the MSX is a Beeline type, I have a lot of reading to do about these. The MSX’s I saw in Norwich ROC and Bawburgh were earlier, they had a huge removable disk, I have one from Bawburgh at home, that and a power strip was all I could save at the time. I found a box of MSX disks in our storage too; I reckon I might need them.
We put some lights into the MSX racks as the front panel is opaque Perspex and the units cannot be powered up yet, the cabinets are quite rough showing surface rust and will need to be treated and possibly sprayed. I have tidied up the power so James can turn on the working gear in the BT Room and Main Operations at the start of the day.
Most of the afternoon was spent making up information cards for the equipment I have been working on, this took some time but I am pleased with the results.