Re: Hookflash and Ground Start Analog CO Trunks From PABX

A flash was (and still is, I believe) never intended to be passed from one
> switch to another. It is a means for the subscriber (phone) to signal the > nearest switch in the chain. > It appears that your equipment can serve either as a switch (PBX) or > as (dumb) terminal equipment (CENTREX). When a CO termination is > ground start, that makes it a trunk between two switches and by design > will not pass a flash. When it is loop start, it is a line and will > pass the flash. > The difference between a PBX "trunk" and a Centrex "line" is not just > one of terminology. There are technical design differences between > the two. This was true when there was only one supplier for the > network and a lot of these standards carried well beyond the date of > deregulation. The fact that they offered you a solution by changing > cards probably means that this "standard" has been corrupted. > One final thought: At the CO end, a ground start PBX trunk originally > was not capable of recognizing a momentary open as a flash. Thus, any > momentary open exceeding 20 ms (or so) would effect a disconnect. > That might still be true. > Has the LEC really offered to provide you ground start Centrex lines? > At one time those were mutually exclusive. > [TELECOM Digest Editor's Note: Actually, on my PBXtra, which goes > under the brand name 'Total Com' and is manufactured by ACNC at the > phone number 630-241-2800, (but distributed by Mike Sandman through > his online catalog
formatting link
[and he is a good friend of the > Digest and well trusted on the net]) you _can_ pass along a hookflash > to the next switch down the line, i.e. the central office.

Do you even understand the difference between a _POTS_ (analog "loop start") line, and a "ground start" (aka "wink start") *trunk* line?

Does your "Total Com" connect to the C.O. with POTS lines?

If so, the fact that "flash" works with _your_ system it totally irrelevant to the question of passing flash on a C.O. "ground start"

*TRUNK* line. [[.. balance of 'ignorance in action' snipped ..]] [TELECOM Digest Editor's Note: It is always so pleasant to receive your replies, since you phrase them in such a congenial way, and pepper them in your own, sort of special way. I think I know the difference between loop start and ground start lines. On older, ground start payphones for example, a coin deposited would trigger a metal 'finger' like thing which would apply ground to the line. Children used to stick a pin in the handset cord of a payphone to get the same results.

The TotalCom Pbxtra device connects to whatever it connects to (mine does have a POTS line (dial 9+), an VOIP line (dial 8+) and a Cingular Wireless cell phone (dial 7+) and other 'local' extensions (dial 100 through 104.) All I said was flashing during a call, then dialing *6 causes a hookflash to be sent back to whatever switch is next in line. It does it through software, I think. You can also program the entire system (as opposed to individual stations) to have *5 apply ground. I do not know how to install that program; I have never studied it. The various system-wide programs it is capable of doing are accomplished by shorting two pins on the RS-232 connector on the bottom, then using the station plugged into the zero port to dial in the desired program codes. By itself, the PBXtra can do _nothing_; the entire unit has to be programmed from the zero port with a jumper attached through the RS-232 port, much as we used to program the old Motorola 'brick phones' by reversing two leads on the battery connector. PAT]