Hi, I recently connected a Micro-Node RTCM to an ICOM FR6000 UHF repeater. The FR5000/6000 has a DB25 auxiliary connector on the rear. Here is the sable pin-out I used. Maybe this helps someone else. FR6000 RTCM ---------------------------------------------------------------------- Pin 11 - 12VDC Out ------------------ Pin 1 +V In Pin 8 - MOD IN ------------------------- Pin 2 TX Audio Pin 9 Discriminator ------------------- Pin 3 RX Audio Pin 21 Analog Audible Out -------- Pin 4 CTCSS In Pin 14 GND------------------------------ Pin 5 GND Pin 19 EPTT ---------------------------- Pin 7 PTT DB25 Shell --- soldered to braid---DB9 Shell Programming FR6000. Configured for CTCSS on Receive, no CTCSS on transmit. Program Pin 21 I/O for Audible Out which is a signal indication when the receiver is unmuted by squelch/tone. Program Pin 19 I/O for EPTT - External PTT Best, Randy W3RWN / VE3RWN San Antonio, TX