atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Telecom Service & Providers Analog trunks-half Duplex

We are having an issue with or analog trunks coming from the CO. Well, I believe it's an issue is with the trunks.
When we call out through any analog trunk, the call connects fine but when talking to the customer then conversation is like we are talking on half deplex devices. Only one person can speak at a time, because if they talk at the same time one person will get cut off.
Could this be a telco issue, because when we call inter office the calls are fine and if we route calls out another site's trunks from the site in question the calls are fine. So the one thing in common with this issue is the analog trunks.
Is there anything I can suggest to Telco about fixing this. They did come out and replace something at the demark and that didn't help.

What kind of trunks and what kind of service?

They are suppose to be POTS lines.

I've never heard of this problem on POTS. If this is all calls to all customers and you have the same problem from the DEMARC with a butt set, just report to the LEC. If this is just to one particular customer they may have a switch problem or are not using POTS for service.

The only thing I can think of that may cause this problem on POTS is if you're being served by a local carrier due to lack of cable pairs.

I guess that is one thing I didn't do is test at the Demark, I'll give it a try.

Also the lines might have had some sort of Centrex service on them at one time or another. Be the Telco reprovisioned to POTS, if they missed something on the conversion could that create this issue?

Centrex is nothing more than an off prem PBX service I can't think of anything that would cause your problem by simply removing the Centrex features.

What phone system you are using? Are you talking about been cut off on speaker or regular handset? If this is regular handsets then most definitely you are connected to IP switch at provider's side.

The site phone system is IP (shoretel) which has no issue what so ever with connecting to loopstart trunks. Yes it is the handset and when connected to a customer on the outside, any noise or both talking at once one of the calls will get muted.
You ever run into this before?

Well guys could this be "talker cut off" carrier trouble?

Jim,
talker cut off?????

"Talking Off" was a condition that was rarely reported (at least in my experience). It occurred when a person's voice had the right (or wrong!) tonal quality that would actually disconnect the circuit.

I saw it most often with women with higher pitched voices and very often it occurred with ancillary equipment, like dictation trunks.

Though we did have one guy with false teeth who, when he got angry the air whistled around the teeth and would disconnect a particular piece of carrier equipment.

Sam

That's when all LD was controled by SF signaling 2600hz. We'd put filters on the "old" ladys line.

Me thinks this is another by product of VOIP. Let's reinvent the wheel.

Try hooking a modem up to one of the lines, and calling out to an ISP or something.

You don't even need an active account; you can make the modem connection regardless, and if you *can*... then the line isn't half duplex.

But: fax and data modems send a tone that turns off echo-cancellers, and if that test fails, but you still can't do full-duplex voice, then I'd bet you have an echo-can stuck somewhere.

Does this happen:

1) On local calls to the same prefix
2) On in-state calls to the same area code
3) On LD calls to a different area code?

It's also possible you could be on a SLC-96 or some other sort of pair-gain system, and *it* has something stuck and needs to be kicked.

Definitely, though, try testing at the demarc, butt-set or otherwise, and make sure it's happening.

Best way to demonstrate it to a repair guy is to call a friend and have them put you on music-on-hold.

Bill -

You're right. That was an Analog Carrier in Kansas that was giving us the trouble. The guy was the CEO of a company and the calls came from /went to somewhere in the Midwest - all routed through one Toll Center in Kansas. When he got angry he "whistled" and that knocked out the carrier. We had too many trunks to filter and while AT&T identified the problem they wouldn't fix it. We changed the LD carier to MCI and the problem went away.

The Dictaphone circuits were a problem well into the '90s.

VOIP seems bound and determined to recreate all the troubles and growing pains we went through. Makes no sense to me.

Sam

I'd like to throw in a slight derail, here...

Please distinguish, when you're griping, between Voice over *IP*, which works just fine, generally, and Voice over *The Internet*, which can be miserable, if you don't know *exactly* what you're doing...

I will test at D-marc, but I don't know if that is a true test one wat or another. If I disconnect at D-marc and test and I don't get the half duplex issue, does that truely mean that there isn't an issue with telco? Because connecting to a butt set is different then then connecting the trunks to a VOIP or for that matter a TDM system.
Am I way off on that theory and I should just follow my findings from the D-marc test?

Correct... this would indicate the problem is with your equipment.

I have been experiencing the exact same problem you've described here. Loop start trunks with a Shoretel system. Been installing Shoretel for 7 years and this is a first. Tested at dmarc with butt set and calls sound fine. From a handset on the system, however, we get the half-duplex effect - one way only though. Internal users cannot hear the outside caller if they talk at the same time. I am baffled. Have you found a solution for this yet?

Hello dwohlbruck and ... PM sent.

never had this happen on our ShoreTel system. lot of sites, lot of trunks. so be gentle, those of you pointing with glee at all things VoIP, saying "told you so!".

network healthy? no speed/duplex mismatches? event logs clean? looked at your TMSncc logs to see what the system thought was happening with that call? opened a ticket with TAC? rebooted that shoretel switch? looked to see if this is a known issue with whatever software level/build number you're on?

worked my way through the forums I read, nothing jumped out at me. same at ShoreTel's site, though my keyword search could be off.

shoretel.com Knowledge Base article KB11044 might help.

just saw a similar problem described over at shoretelforums.com, you might compare notes.

I'd appreciate knowing the fix, once you find it.

Network is fine. Ext to ext calls or ext to voicemail calls are perfect. event logs clean. TMSNcc indicates normal call setup and teardown. not only rebooted st switch but swapped it out completely. searched build notes and kb for similar problem - nothing. KB11044 has to do with one way audio usually associated with routing problems - not the case here. Starting to think this is an overreacting echo canceller. Just don't know whether it's Shoretel or telco.

Yeah same here, good network, internal calls good, nothing in logs, swapped out sg-30 to first GEN switch 40/08 didn't matter, even a new phone for testing didn't matter and I upgarded to the latest 8.1 GA. I'm going to be on site next week to pull an audio and packet capture.
I though about the echo, handset gain, sidetone, but all of the sites use the same boot files and none of the other sites have this issue.

If the voltage on the telco lines are not at 48v, maybe a little lower would that cause this problem? I never took a reading on the voltage.