Here is a clip about PIN 4 in the Accessory plug of a GM300. 4 Programmable Output Only This is a radio output port. It is an open collector output which saturates to A+ supply when active. It is normally used to drive an external relay or sense lead. It duplicates the function of J3-3 of the five pin logic board. When active it can source a maximum current of 250 mA. The pin has a 10 K ohm resistor pull-down to ground on the logic board. and uses a PNP transistor to switch it up to 12V. This pin does not work as an active low pin (i.e. pulling something to ground), only as an active high (that is dragging something up to +12v). If you want an active high output to drive a reed relay which has the other side of the coil to ground, this is your pin (but don't forget to check that the backwards diode is present on the coil pins). Bill Hurlock -----Original Message----- From: app_rpt-users-bounces@ohnosec.org [mailto:app_rpt-users-bounces@ohnosec.org] On Behalf Of app_rpt-users-request@ohnosec.org Sent: Friday, May 10, 2013 12:00 PM To: app_rpt-users@ohnosec.org Subject: App_rpt-users Digest, Vol 51, Issue 9 Send App_rpt-users mailing list submissions to app_rpt-users@ohnosec.org To subscribe or unsubscribe via the World Wide Web, visit http://ohnosec.org/cgi-bin/mailman/listinfo/app_rpt-users or, via email, send a message with subject or body 'help' to app_rpt-users-request@ohnosec.org You can reach the person managing the list at app_rpt-users-owner@ohnosec.org When replying, please edit your Subject line so it is more specific than "Re: Contents of App_rpt-users digest..."