> >> However, outbound calls are hit or miss. Sometimes they work fine and > >> other times we get a "you must first dial a 1 or 0" message back from > >> telco when dialing out standard POTS lines. > > > > > > Did you get this working yet? > > > > > Yes, it does seem to be working fine now by adding the "w"s to the > dialstring.
The following is intended to provide a little bit of info as to why the "w" is needed when dialing via some central offices (pstn fxo's). Several telephone companies still have older electro-mechanical central office switches. The majority of these older switches have a bank of "dtmf receivers" that are shared across all pstn lines, and are only attached to each pstn line during the initial few seconds of a pstn call. (There might be 20 or 30 receivers for a central office switch that supports 5,000 pstn lines.) When asterisk seizes the pstn line (goes off-hook), dial tone is usually provided within a second or two. However, the dtmf receiver may or may not be attached and ready to receive dtmf digits in that short period of time. (If the central office switch is slightly under-engneered, there could also be a shortage of dtmf receivers that _could_ result in a receiver not being attached to the pstn line within the first second or so.) One or more "w" in the dial string causes asterisk to delay sending the dtmf digits, compensating for the delayed attachment of the dtmf receiver in those central offices. In very very general terms, the delay is only seen when interfacing with analog pstn lines. (Newer central office switches that support isdn typically are not designed/engineered with this one-to-many dtmf receiver arrangement.) _______________________________________________ Asterisk-Users mailing list Asterisk-Users@lists.digium.com http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
