W3 Astro Spectra Power-up without head

[NSPD]

I have a few W3 radios that I need to power up and read, although I don't have W3 heads for them.

I have done this with W7 and W9 units by jumping pins 20 and 22 on the control cable connector, but I know the W3 uses a different interface. Anyone know what pins I can jump to power these units up?

Thanks!

[motorola_otaku]

From the Astro control head manual:

3.1.10 Power On/Off
The HHCH has the ability to turn a host radio on or off by activating S6, which then places a
momentary logic low on the Mic Hi line. This is detected by appropriate circuitry in the host radio,
which then reverses the power on/off state of the radio. Since the microphone power is supplied by a
switched Opt B+ line from the radio, the microphone power on/off state follows that of the radio.