I installed a Comswitch 5500 on a wired Verizon 2 line ksu-less phone system, don't know model number. This has 5 phones on it, if I hook up more than two phones the line lamp lights. The voltage out of the Comswitch on the phone port side is 30 volts, this voltage doesn't drop as I add phones. I tried splitting the phones between the phone out port and the TAD out port no help, tried reversing the line, in and out no help. Presently I've removed the Comswitch. Comswitch tech support has never heard of this problem and says it must be a compatibility problem between that phone type and the Comswitch. I've only put this on SLT's and KSU's and never had a problem, but I've never tried putting them on a ksu-less system before. Has anyone else ever had or heard of this problem?

Any chance the Comswitch is on the IC-C.O. shared line? Just a guess, maybe the IC carrier is messing with the Comswitch?

Not sure what IC is but this is copper all the way to the C.O. and is an ILEC.

OK I called tech support for The Stick. The Stick puts out 48volts idle voltage. I'm thinking the 30volts put out by the comswitch is just too close to the drop in voltage where the lamp lights and even a marginal drop will cause it. So if I can get my customer to agree I'm going to try the stick.

I think that is going to be the only solution. As you know, two line phones are very funny about perfect line conditions. The idle voltage is one thing, but the off-hook voltage is where the real trouble begins.

I'm thinking the same Ed. Since the stick is twice what the comswitch is my customer is thinking about it.

IC (Intercom). Yes the stand alone phones sometimes use second pair for IC etc.(FM etc ).

I think the circuit would ride outside the physical
wire itself but also could be your factor in getting
it to work.

Myself i don't know if i would invest any time in getting it to work 100 per cent, that is if you expect to get paid for your effort.

Geesh, intercom didn't enter my mind, now that I re-read it, it's obvious (sorry Lightninghorse). Line two was the line in question, the ones I've seen the data and intercom ran on the 1st line. I'm sure that can vary brand to brand though. I did try frogging line one and two with the same results.
Does that statement mean you've experienced trouble putting a fax switch on these non-KSU phone systems?

Thanks for setting me straight on the IC.

I installed The Stick, it seems to be working fine. It sure appears to me it was the marginal voltage output of the comswitch.

Good for The Stick. If I had done this, "I/C CO line" it might have made some sense! Ya think? Sorry, my short-hand sometimes only makes sense to me!

Nah, I just didn't have my brain in gear when I read it. It was clear after it was pointed out and I went back and re-read it.