Rich Adamson wrote:
Perhaps, bu AFAIK, there are NONE left in North America, certainly none left in the US or Canada.Yes, it does seem to be working fine now by adding the "w"s to the dialstring.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?
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 onlyCrossbar systems. Step by step systems converted to DTMF had DTMF to pulse dedicated to each linefinder.
attached to each pstn line during the initial few seconds of a pstn
call.
Not so sure about that. IF dial tone is provided, the receiver is ready and waiting,(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,
OR overloaded,
None of this excuses the inability or unwillingness of Asterisk to listen for Dial Tone. The modem card used for single FXO ( the X100P and clones ) certainly had that ability in its former life as a modem.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.)
Has this ever been reported as a bug?
Or would this be considered a "feature request" , along with detection of stutter dial tone on analog lines.
It seems to be necessary in electronic offices as well, when dial tone is delayed.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.
John Novack
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