atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Telecom Service & Providers Ground start Loop

I understand the superiority of ground start vs loop start. I also understand 2-wire and 4-wire metallic E&M and analog DID trunks. What I don't understand is where are telcos still installing analog trunks today? (and I do mean trunks and not lines). since the 90s, I have installed very few analog trunks. A few analog DIDs maybe, and an occasional E&M but is anyone still ordering and installing them in the 21st century? The only reason I can see the value of requesting an analog trunk today is when a loop start line is experiencing problems that the TelCo says is within normal specs. Requesting an upgrade to trunk status is supposed to make the TelCo actually qualify the line to ensure the best possible delivery of the trunk. (I think Mike Sandman has even referred to that last part as a solution as to when a subscriber has audio problems).

Sam, I think you may have said earlier that some schools in your neck of the woods are still using them? And if so, why? Unless there is a grandfathered price advantage, it just isn't sinking in for me. Do any of us still have pbx customers with equipment so old that they only work with analog trunks? I don't.

Dave -

Here in NYC, many years ago I discovered that NY Tel would sell you a GS Trunk but actually only deliver a GS Line. It had the opportunity of developing into a major scandal and class-action law suit, but politics squashed it,

I was curious if small systems (people that needed less then the 24 trunks a T-1 would deliver) still used GSTs. Admittedly my experience is ancient, but back in the day when I installed key systems and small PBXs, almost all of them had less then 24 CO circuits.

Sam

Old thread, I know, but I had to chime in.

My employer's Option 11 is still using ground start trunks. We also recently added more trunks and the CLEC had no problem hooking up more ground start trunks. We are now up to 23 trunks for the Option 11. Our vendor suggested that we look into a PRI to possibly save some money. I called our CLEC and their response was "What's a PRI?", so we still have GSTs.

Also, all of our trunks are used both for incoming and outgoing calls, so I would not want them to be loop start. Glare could potentially be an issue.

I have talked to a few techs, both with our CLEC and AT&T. They all have no problem selling and servicing GSTs. At least where I live, GST is still the standard for PBXs.

As a side note, once in a while we have to call for service on one of our lines. About half the time, the CLEC will fix the problem but also convert the line to loop start. I always have to call them back to get the problem solved. The worst case was when the LEC (Ameritech at the time) decided to move many of our lines into a PairGain because they were running out of space. It took AT&T, the CLEC, and our department weeks to get the problem fixed. The CLEC didn't realize that you can't run GST through the PairGain and Ameritech didn't realize (or didn't care) we had ground start trunks!

-Nelson

Thanks for chiming in, even on an older post...

I’m sure a lot of us have felt that pain when dealing with GS circuits and doing cut-overs to them… And that’s from BOTH side of the demarc.

I do need to mention though... Pair gain systems DO, do ground start lines. Not every voice channel card is capable of GS, but I have never run across any pair gain system that didn’t have channel cards that could be optioned for GS.

I do need to mention though... Pair gain systems DO, do ground start lines. Not every voice channel card is capable of GS, but I have never run across any pair gain system that didn’t have channel cards that could be optioned for GS.

Good to know, thanks Bryan. Since so many people have gotten rid of their phone line in favor of cellular recently, the phone company doesn't seem to be so concerned about running out of space as they were a few years ago. So, they have since moved all our GSTs back off the PairGain.

After they moved our trunks off the pair gain, they then moved our loop start alarm lines onto the pair gain. We then started having problems with our alarms. The alarm company kept calling us complaining of communication errors about three times a week. Again, the CLEC, SBC, and our alarm company went 'round and 'round about where the problem was. SBC kept replacing cards in the pair gain. Finally, they moved all our lines back off the pair gain and everyone was happy again. We've had no trouble since.

-Nelson

The next time someone doesn't know what a PRI is; say to them that it's ISDN.

With T1 service, Ground Start trunks are not as common today as they once were. GS was often requested when a D4 channelbank (such as a Newbridge 3624) was needed to interface the T1 to a telephone system that did not have a T1 card. Today the most common form of inband trunk signaling is T1E&M Wink.

Loop Start trunks on a T1 circuit are bad news for incoming calls. If an auto attendant is involved and the caller hangs up during the greeting, the system may not see a disconnect from the CO which can result in phantom ringing.

I was always told ISDN equaled "IT STILL DOES NOTHING"

Jim, I too had heard it in a similar phrase....when asked what ISDN was all about the answer was "I Still Don't kNow".....

:shrug:

GS, PRI, E&M, Wink they're really all the same principle. The signalling controls the circuit, not the loop controls the circuit.