TASS Switching...
TASS Switching
In 1969 there were 367 telegraph offices connected to the network. Connections were set up by dial controlled pulses, through the NINE switching centres forming the T.A.S. System.

John Lamble recalls... "Final Selectors - all TASS circuits to the Telegram Offices were only 3 digits - The one office I always remember is JTS 765, Heathrow Airport, where if I remember rightly, telegraphists staged some industrial action when the Post Office introduced new teleprinters that had 3 rows of keys as opposed to the standard 4 rows."  


SLC: Station Line Circuit equipment consisting of a uniselector and relay set © John Lamble 1977. 
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Trunk Control North
1st Selectors
1st Selectors: SLCs were connected directly to these First Selectors.





Photo © John Lamble 1977. 
2nd Selectors
2nd Selectors: The first two racks are Second Selectors the rest are Final Selectors.





Photo © John Lamble 1977. 
Other VF test facilities
Other VF test facilities - including separate send and receive Telegraph Distortion Measuring Sets, TDMS.






Photo © John Lamble 1977. 
AMVF racks
Amplitude Modulated telegraph Voice Frequency equipment racks - Type 4. Each VF system contained 24 channels operating in the commercial speech range.






Photo © John Lamble 1977. 
FSVF rack
Frequency Shift VF rack - 24 channels per system.







Photo © John Lamble 1977. 
Fault Reporting
This shows the combined fault reporting point for both JTS and L/TCN VFT, originally they were separate. In the background are the TASS ECBs (Engineering Control Boards) used to access individual circuits, the map high up on the right is of the Shell-Mex BP network.





Photo © John Lamble 1977. 
Intermediate Distribution Frame (IDF)
This was the IDF (Intermediate Distribution Frame) for JTS situated behind the ECBs.







Photo © John Lamble 1977. 
MONTE
MOTNE Phase 3: Control equipment for the collection and distribution of weather data from UK airports and Europe operating at 75 baud for the CAA.


An improved version -MOTNE Phase 4 - was installed at St. Botolphs - I think in the mid 70s.





Photo © John Lamble 1977. 
   
More TCN Photos
VF test tabs
Test Tablets for accessing individual system channels.



Photo © John Lamble 1977. 
A type 4 channel panel in the workshop jig.
A Type 4 AMVF Channel Panel mounted in the workshop jig.



Photo © John Lamble 1977. 
S and T test sets
S and T test sets.



Photo © John Lamble 1977. 
Design, images and text compiled by © Light-Straw. With thanks to John Lamble.
Page last updated 2nd March 2011. Checked June 2021.

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