[GreenKeys] ebay "Teletype Message Numbering Module"

[Nick England]

ZCZC NYWCH 001

Teletype 173520 Message Identification And Numbering Module Assembly

Howdy gang - I identified this eBay item as the message numbering unit used
in 28 Torn Tape Relay equipment, in particular the Transmitter Group which
has two triple-TD trays and 6 of these numbering units. The military
version is TT-333A/UG and you can see photos at
http://www.navy-radio.com/tty-relay-equip.htm
I also got front/rear views from the eBay seller and added them a little
further down the page.

I have one triple-TD tray and got 3 of these numbering units from the eBay
seller with the intent of creating a "half-size" TT-333A/UG.

As Jim Haynes said, these units generate the header for a tape that you are
going to transmit. The stepper relay connects 15 sequential characters in
5-wire parallel to the distributor on the corresponding TD in the equipment
cabinet. There is also a tandem mode where one numbering unit controls two
TDs in alternating sequence so that you can load one message tape while the
other is being transmitted. Clever lads, those Teletype chaps....

When you load a tape and switch to RUN on a TD, the numbering unit first
generates the following sequence:
(LTR) ZCZC ABCDE (FIG) 123 (LTR) (start_message_tape)
where 123 is from the sequential message number counter,  ABC are
customer-wired characters, and DE are customer-defined characters by two
plug-in code cards (visible in the front photo).

The eBay seller has some more and will post them for sale I presume - I
got 3 of them for $60 ea. (yeah, too much but better than the original $950
ea. listing...)

If you are interested in these things, I will be scanning and posting
description, parts, and wiring diagrams over the next couple of weeks.

Cheers,
 Nick England K4NYW
www.navy-radio.com
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