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

"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.