GE Concord 4 keypad help

I have a 60-746-01 keypad. I have my Concord 4 panel on the second floor. I have a 22/4 unshielded copper security system cable running from the attic to the basement. I use 2 conductors in this cable for a 24v NAC (I know it’s undersized, working on replacing it). The other 2 conductors are my Bus A and Bus B connections. The keypad is located in the basement. It’s estimated to be less than 150 feet of cable. I’ve also got a mix of 18/2 shielded stranded copper wire on both ends of this cable as the original cable wasn’t long enough. The keypad is powered by the auxiliary 12v output of a Honeywell Vista 20-P. I’ve made sure that the bus connections are correct, and the keypad will display broadcasted messages such as ENTER CODE and some messages from the system programming menu, but it doesn’t connect with the panel. I’ve entered the device ID manually, and swapped it with a keypad previously enrolled. This is purely a connection problem. Is this caused by electrical interference or does the keypad perhaps need to be powered by my panel? I’ve tried everything, manual bus scans, swapping the device. How could I fix this?

It is entirely possible the keypad has to be powered from the panel it communicates with. We had several fire alarm annunciators that would only work when powered from the panel where the communication starts. According to the keypad manual I found #22 wire can be used up to 300 feet.

Take the keypad to the panel and connect it there to see if it works. Or disconnect the NAC devices and use that pair to power the keypad temporarily from the panel it communicates with. The black (GND) wire may also be part of the communication circuit. I saw in the Concord 4 manual I found that the black wire on the touchpad with terminals is labeled GND/COM for common. That may point to the black wire being part of the communication circuit.

I’ve come home to find that the keypad automatically enrolled itself, worked for an unknown length of time, then stopped working, causing a bus failure trouble. So I went to check it out, literally only touched the wires, and it started working again! I didn’t do a thing except put my finger on the cable. I’m not sure how long it will work, so I’ll have to check again later.