Lyle Giese wrote: > Philipp Kempgen wrote: >> Steve Totaro schrieb: >> >>> On Wed, Jul 22, 2009 at 12:07 PM, Steve Underwood <ste...@coppice.org>wrote: >>> >>>> Olivier wrote: >>>> >>>>> I've got a general question about analog gateways (Xorcom, Audiocodes, >>>>> Patton, ...) . >>>>> Is it usual for analog gateways to detect when an analog phone is >>>>> plugged in or out ? >>>>> If positive, would it be then useful to send "qualify" queries for >>>>> each connect phone (I'm implying here that an analog gateway would >>>>> then reply appropriately for qualify query. >>>>> >>>> Unless there is a call in progress the switch has no idea what phones >>>> might be plugged or unplugged. Nothing happens on the line what it could >>>> detect. >>>> >> >> >>> It certainly would seem "possible" and would be a great feature request. >>> >>> There probably is no circuitry existing to do it, but I would assume that >>> ohms, volts, or something could be measured while sending a small amount of >>> voltage down the FXS lines. >>> >> >> Bonus point will be given for detecting the phone model and color >> as well. ;-) >> >> >> Philipp Kempgen >> > Yes, it's technically possible for the phone company to determine if > there is a set or something connected to a phone line. It involved > hitting the line with +130v dc test voltage and reversing it quickly > and seeing how much capacatance kick there is. This kind of testing > is normal for telco CO lines. > > FXS chan units or gateways normally do NOT have this built into them. > The only exception I know about is SLC(Subscriber Line Concentrator, > which is a generiac term for fiber or digital lines feed to telco > boxes in the field). And even there the process was to have a cut-in > relay and connect the out cable pair back to the CO via a dedicated > copper pair to do these tests via a device called a PairGain Test > Controller. I know because I was an 'expert' on them and traveled > around going from telco CO to CO fixing them. > > In other words, there is some circuitry involved in doing these tests > and I don't see any PBX, FXS chan unit or gateway manufacturer rushing > to add more to this to their product line. They have not done it yet > and I don't see anyone other than the phone company willing to spend > the money to make it happen. > > To keep this on topic for Philipp's remark, the only bonus points we > assigned was to correctly guess how many phones were attached to the > phone line<GRIN>! Sane people just make a call, and see if the darned thing works. :-)
Steve _______________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users