sundance-communications.com/forum Forums Other TDM Phone Systems Vertical Telephones & Systems SBX line voltage

We have a SBX that when the I press a line buttons 1-3 all I get is a clicking sound followed by a CO release busy. Line 4 is fine. I get the same thing when dialing 9 if I busy out line 4. If I swap line 4 with lines 1-3 they are fine so it is definately a line issue. Tech support tells me it is because the line voltage is too high. I am reading 55 volts on all the lines including line 4. I know the lines should be 48 volts but 55 does not seem that high. I know there are line amplifiers out there but do they make anything that will lower the voltage on a line. I really can't see Verizon helping me with this since the lines are fine when testing with a butt set.

One other question has anyone had any issues with caller ID on a wave 2500 with analog lines?

have you looked at loop current ?

have you checked the lines a the demark with a buttset ?

I am getting 35 mA off hook. Unfortionately I can't test the current on hook. The lines are all testing fine at the demarc except for the voltage being high. I can go off hook on all the lines and get dial tone.

May want a different system SBX is very picky with line conditions.

Apparently. I have an old partner acs in between the SBX and the dmarc. Thats keeping the customer happy. It looks like crap though. I'm still waiting to hear back from engineering on this.

It's something that probably won't change, it's just the way they are. One of the biggest problems with the SBX's, other than that they're pretty solid. We had a few where differing line conditions caused problems also.

The line current is probably too high. You need to build it out with resistors, or get a Sandman loop current attenuator. 25 mils should be enough.

The resistor build out can be as simple as adding a 100 ohm resistor to both tip & ring. This cheap fix costs next to nothing and may do the trick.

Call me crazy, and I probably am, but shouldn't a system's CO line ports be more tolerant of variables as long as they are in compliance with FCC mandates? Just asking.

Ed, I recall older posts about the effects of high current and voltage. I think members described their systems as behaving in different ways. I used to see echo on Vodavi analog systems and didn't Hal say the ACS sometimes burned out the CO Circuit packs on high line voltage?