SENDER No. 9A and 9B
The Sender No. 9 was produced by PYE-TMC and intended as a retrofit for the Public Exchange Manual Switchboards. Most public exchanges had their dials replaced with this sender. A Key-Unit No. 4/1 was plugged into the Sender.
The Sender No. 9A just had terminations. The Sender No. 9B-1 had a flexible lead with a Plug No. 616A. This connected to a Jack No. 83A which was wired to the switchboards power and dial terminations. On the PMBX No. 1A a Voltage Regulator was required and wired into the power connections.
They could work on either 24v or 50v DC powered switchboards.
The Key-Unit No 4/1A, 4/1B or 4/1C was connected the jack on the Sender.
Terminations on the Sender No. 9
* If used on a 25v power supply then A, B and C are all linked together.
On 50v systems only A is connected to power.
Sender No. 9A front view
Sender No. 9A rear view (showing solder terminations)
Sender No. 9B-1 front view
Last revised: February 24, 2021