tel@cdsdb1.att.com (02/06/91)
With regard to recent discussions about getting answer supervision from the local phone companies, it is possible. I just had sixteen outbound trunks installed by New Jersey Bell that were configured to provide answer supervision. They are called Wink Start trunks and they are not a tariffed offering. I had to wait for several weeks of Special Rate Approval for these trunks, and they are not exactly cheap. I think they were something like $100 each to install and $85 per month, plus usage, although I have no idea what standard tariffed ground start trunks cost as a comparison. I was told that being AT&T had nothing to do with getting these trunks approved and that anyone who wants to pay for them can get them. I was always under the impression that the phone companies weren't permitted to offer non-tariffed services, but apparently that's not so. Can anybody explain this? The way I understand it, they work just like standard DID trunks, except reverse. When the PBX wants to place a call, it siezes an available trunk by taking it off hook (This works with a standard phone, also). The CO responds by attaching digit receiving equipment then sending a wink which consists of a momentary reversal of current (A volt meter shows a change from approximatly 6 volts between Tip and Ring to -6 volts and back to 6 volts) (My polarity may be backward ... I wasn't paying attention to which was tip and which was ring). This means the same thing as a dial tone ... i.e. go ahead and send digits. The PBX recognizes this wink and sends the digits, which are standard DTMF digits. Again, you can do this with a standard phone. When the called party answers, supervision is provided to the PBX by means of a reversal of line current (from 6 to -6 volts or whatever). When the called party disconnects, line current flips again to signal the disconnect. I tried using these trunks on my AT&T Voice Power VP4 boards which are designed to sense presence of current, as well as current reversal, and it worked like a charm. My program watched for the initial wink and sent the DTMF digits. When the called party answered, it sensed the reversal of current, and when they hung up, it again sensed the reversal of current. If you have any questions about these, please send me email. I don't know if I'll be able to tell you more than what I said here, but I'll try. Disclaimer: This represents the way I understand (or mis-understand) how things are. It may be wrong and does not represent any official statements of AT&T or NJ Bell or me. Tom Lowe tel@hound.ATT.COM AT&T Bell Labs, Holmdel, NJ 908-949-0428 [Moderator's Note: The way telco handles non-tariffed special situations is to go and have a tariff written for that customer. There is an overall master tariff which covers 'special situations', and this tariff allows for filing tariffs subscriber by subscriber as needed. If they see some profit in your proposal, they'll find a way to do it and get it tariffed! PAT]