Difference between CO "trunk" and "line"??

[BobbR]

Can someone please enlighten me of the difference between a CO "trunk" and "line"? Reason for asking is that we have both type of lines connected to our Legends. Several trunks are in one hunt group, several lines are in another. The trunks are ground-start while lines are loop-start. Voice quality wise, I see no difference between the two, nor does either Legend seem to care. We are using no special services other than the hunting. It's a long story why we have both, and the trunks are considerably more expensive. SBC, of course, says they cannot be changed to lines due to "tariffs." What must be done to change from one to the other, or, why should I not? Thanks.

 

[Pepperz]

There is no difference between a trunk and line. There is however a difference between a ground start and loop start line. The Magix and Legends can handle both, if the right card is used. A ground start trunk or line would give a better disconnect, and were a little more reliable than loop starts, but now it makes no difference. If you have ground start trunks or lines, then the particular port it plugs into must be programmed as ground start in order to make an outgoing call. An inbound call will still work programmed or not.
Is that clear or muddy?

TipHelp@charter.net

 

[BobbR]

Very clear, and I understand that Legend can handle either. What is muddy is the provider's position that the "trunk" is a premium "line," and charges accordingly. My queries to their techs are answered with 'no difference.' I feel trapped, in that after having acquired "trunks," they cannot be gotten rid of in favor of "lines."

 

[Pepperz]

Balderdash! Replace whatever you want, and if you have a choice in the area, with whomever you want! Hunt groups are only needed from the CO, if they tie into a certain number that customers use to contact the company. Sometimes, (actually usually) time goes by, company needs change, notes are lost, projects changed or cancelled, and you are left with a mess of lines and TRUNKS, that no longer make sense. The LAST person with the right answer is the phone company, because if you figure it out, they sell fewer lines. The first place to start if you're thinning down lines is the phone bill, you (if the Sys Admin for the company) should know the purpose, of each line, and whether or not it goes through your Legend.
Their "premium" service may tie into a special promotion or something they are trying to hold onto. It could be that at the time the package was sold to your company, that a hunt group had to be ground start, (tarrif rules perhaps), but rules have changed a lot lately.
Again best advice is to inventory what you have, determine what you need, and see if there is a match, if not adjust.

TipHelp@charter.net

 

[GoKings]

BobbR...What Pepperz is saying is correct in that from a PBX standpoint there really is very little difference between a line and a trunk. However, there truly is a difference between the two, especially from the service provider (SBC in this case). I won't really bore you with the details, but to make it simple, SBC can change those from trunks to lines, but will have to order new lines to your site and port the numbers from the trunks to the lines. This will likely create install charges for you for the new lines. Your trunks, in this case, are GS. Ground start trunks are preferrable to a PBX in that the PBX itself will be providing the disconnect on those trunks. LS lines, however, require that the CO provide disconnect. Even with LS Reliable Disconnect set to Yes in your Merlin, these lines can still have slow disconnects. What does this mean in the long run? Well, for nickel and dimers, the longer a line takes to disconnect, the more you are being charged, especially if you are still being billed in full minute increments by Bell. Other than that, as Pepperz indicated, there is very little else that an end-user on a PBX will notice.

 

[Tony2Finger]

We've had customers that were required to convert or obtain trunks because of other circuits they required such as having OPX circuits or TIE lines. Just part of Tariffs

 

[franke]

Actually there is a difference between "lines" and "trunks" from the Telco's point of view. The most notable being the line conditioning. For instance there are basically no parameters on a "line", however on a "trunk" the C.O. must ensure no more than a -2dB loss on turn up and no more than a -4dB loss on a running circuit. It used to be (though I'm not sure it is still so) that an OOS "trunk" had to be restored within 4 hours whereas a "line" had a 72 hour limit. There are more restrictions that apply, hence the greater cost, and you can propably get all the specs from your local provider (I imagine they will charge for the documentation).

franke

 

[Rainman10]

franke is right,

Atleast in my region it used to be that a true "trunk" had a higher volume of approx 6db since it was used in older mechanical switches proned to db loss. As PBX technology changed the use of each and the terminology became interchangeable. However, older ground start lines were actually engineered as special circuits with particular values and in many areas are still treated as such in respects to maintenance. Chances are if you have some older and newer ground start trunks, and you have SBC, the older trunks are serviced by a special circuit repairmen and the newer are serviced by a residental grade repairmen. Wether or not it is an engineered circuit dictates what type of repaiman they send out. There are some other variables depending on the type of CO and wether or not SBC has done any appropriate hardware upgrades to it.

You can change them if you really want to. Cancel the old and create a new provisioning order with SBC for the new. Ground start are better though, for all the reasons mentioned in this thread.

 

[BobbR]

Thanks to all responders, I appreciate the enlightenment. I am considering changing back from a 3rd-party dialtone provider to SBC. One cannot justify lousy service by saving a few bucks. About 1/4 of our 40+ lines are ground start trunks and I can detect no difference in quality or operation over the loop start lines thus my question, with thoughts of changing to save money that route. We will see. Thanks again.

 

[Pepperz]

Bobb, if you have that many lines, you should probably look into getting a T-1, you'd probably save a bundle. T-1's are essentially 24 lines in 1 circuit, simply put, but usually run in the $300-$500 per month variety, with lower long distance charges. 40 lines at about $25 each should be well over $1000 per month. If your company has a suggestion program, may you could win some money by saving them some money. Definitely look into it, though. One other added benefit by doing tis, is then you can change the argument over lines vs. trunks to T-1 vs. PRI !

TipHelp@charter.net

 

[BobbR]

Pepperz, thanks for the suggestion. Actually, the reason for 47 lines is to replace a T-1! Not to belabor this thread but more insight: 18 of the lines are FAX and/or Modem and bypass PBXs, any non-answering modem being shared with a FAX machine. We have three physical locations and three Legends networked (Master-Slave #1 linked via T-1 DSU-DSU our cable, Master-Slave #2 via SBC T-1, due to remote site); a soon-to-be eliminated SuperTrunks T-1 terminates on Slave #1 for all in/out LDX. A couple of years ago when we installed the T-1, I had a vision of eliminating several lines but data from the SMDRs allowed dropping only two. Considering usage peaks and valleys it looks to me that 29 voice lines will handle all the T-1 and local traffic. The cheap(er) line cost and LDX rates from the new vendor, and dropping the T-1, more than offset cost of the lines. Now, in light of lousy service from the new vendor and imminent return to SBC phone service, I need more cost reduction thus the thought of converting the eleven trunks on one Legend to lines. Although it seems we are dumbing-down telephony technology, our traffic volume does not justify cost of a T-1.