Batboard

Hello all, I have a Maxtrac set up as a base.It's being powered by a Motorola A/C power supply.Iwant to power the tone termination panel using the accessory plug on the Maxtrac.I know that pin 13 is the +12 volt supply from the on/off switch but I'm not sure which pin to use for the negative/ground. Any help would be greatly appreciated.Thanks

Pin 7.

http://www.batlabs.com/images/maxacc.gif

kb4mdz wrote:Pin 7.

Pins 7 and 9 are tied together and that IS ground for external accessories.
Pin 13 is switched 13 volts for accys, limit is 1 amp.