Tony Duell ard at p850ug1.demon.co.uk
Thu Dec 9 16:13:04 CST 2010

> Forwarded from the Greenkeys list. 
> Looks like an interesting piece of test gear:
> http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&item=370462778137

> You can either use it as a loop keyer, or, if you need loop power, it will 
> provide that as well.
> You can send distorted signals up to 44 per cent switched bias, and can 
> measure incoming bias and distortion as well.

I still have (and use) a TDMS5 made by ATE (part of Plessey I beleive). 
This is a somewaht simialr thing that wil lsend the Quick Brown Fox 
message (albeint in Baudot only), or a repeated character (set of toggle 
switches) with cotnrollable distortion. It'll also display distortion on 
the incoming signal, test relays for bais and transit time, etc.

Alas I don't have the companion TDMS6 which is a receiver only, but does 
rrater more tests on the incoming signal

Oh, and it is entirely valved (maybe with semiconsductor diodes, but none 
of those new-fangled transistors!) [1]. Yes I ahve the manual includign 
schematics and parts lists.

[1][ In case you'rewondering, the Quick Brown Fox messge is stored on a 
rtoating disk with sping contacts to read off the 5-bit characters. 
There's an exploded view of the mechanism with set-up instruction in the 

I also have a much later test signal geneator (only, no receive fuctions 
at all) made by Trend. I really mustget that going sometime..


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