Juma PA 100D PTT Connection
Posted:
31 Oct 2022 20:28by KK5DB
I am building a special cable for the PTT input on my PA 100D. I would like to confirm that the tip of the 3.5mm "stereo" (3 conductor) plug should be pulled to ground for the PTT to operate. I plan to make the cable with only a connection to the tip and ground (sleeve) of the plug. There will be no connection to the ring on the plug.
Thanks
Dennis
KK5DB
Re: Juma PA 100D PTT Connection
Posted:
01 Nov 2022 13:33by 5B4AIY
Yes, that is correct, the tip of the 3.5mm TIP/RING/SLEEVE plug has to be pulled to ground to put the linear amplifier into transmit. Note that you MUST use a standard stereo plug, that is TIP/RING/SLEEVE, because the sleeve connection repeats the PTT signal, and a mono plug would short this to ground.
The PTT line is pulled up to +12V via a 10K resistor in series with a 1K resistor. (I am attaching the schematic if you do not already have it.) Make sure that your PTT line does not have more than +12V on it when in the RX mode. An open-collector or dry relay contact is ideal.
Adrian, 5B4AIY