Jim, According to the SM-series Service Manual 6880903Z45, pin 7 of the accessory connector and pin 4 of the mike jack are ground. I verified this on a new radio just now.
Confusion sometimes arises because of the way Motorola numbers the pins. When looking in at the accessory connector, with the radio upright, the pins are numbered thus: 15 13 11 9 7 5 3 1 16 14 12 10 8 6 4 2 When looking in at the mike jack, the wires are numbered thus: 8 7 6 5 4 3 2 1 The SM-series Service Manual is still available from Motorola Parts for about $22. 73, Eric Lemmon WB6FLY -----Original Message----- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of kh6...@netscape.net Sent: Sunday, June 13, 2010 11:29 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] SM-120 Assy. connection clarification With no power connected, on the Accessory connection in the back of the unit, which is Ground? Sm-120 reference information states that pin 7 is ground. On my unit, on the Accessory connection in the back of the unit, pin 4 is at ground. I have programmed the Accessory for pin 4 to be COR + PL., pin 9 PTT, pin 11 Rx audio , and pin 3 Tx audio. I noticed that the information on the SM-120 web page stated, in the front, the RJ-45 pin 4 is at ground. Could someone explain, or correct the Accessory connection. Thanks, 73's, Jim Kh6jkg
