[GreenKeys] British Telex Equipment

[Sam Hallas]

I found this document

<http://www.samhallas.co.uk/repository/telegraph/station_equipment.pdf>

while clearing my loft. It's a description of the customer premises 
equipment for the Telex service with circuit diagrams.

I must have copied it in the early 1970s. It's copied with a semi 
photographic process of the time - not Xerox.

Anybody got an idea which book it comes from?

Sam