I used to own a company which made fax switches and yes your devise must "answer" the call to detect the fax CNG tone or wait till voicemail answers and try to detect the CNG tone while the voicemail greeting is being played.
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Adam Goryachev Sent: Monday, May 02, 2005 8:13 PM To: Asterisk Users Mailing List - Non-Commercial Discussion Subject: Re: [Asterisk-Users] Detecting Fax and bad CDRs On Mon, 2005-05-02 at 21:21 -0500, Matthew Boehm wrote: > Here is the current scenario: > > Someone calls my DID. It comes in on PRI. I do "Answer()" then "Wait(1)" to > see if there is a fax tone. If there is, goto fax context and do the fax > thing. > > If no fax tone, then "Dial(SIP/myphone,30)". If I don't answer in the 30 > seconds, goto Voicemail. > > However! If the person were to hangup before the 30 seconds expired, the > channel would get hung up but the disposition in the CDR (along with the > billable seconds) would be inaccurate because I "Answer'd" the call > beforehand. > > Is there a way to change the disposition and the billable seconds to more > accurately reflect what happened? > > This really is only a big deal for inbound 800 calls; because if I answer > the call and it is a person and they hang up before voicemail picks up, I > have to charge the customer for those 10-15 seconds. Plus, I give customers > the ability to see their "missed" calls, which is based on a 0 billable > seconds duration in the CDR. There are two methods for detecting a fax (that I know of). 1) Allocate a specific DID for your faxes, so any call to that number will be a fax 2) Answer the call, listen for the fax tone, and if you receive it, then treat as a fax, else carry on. AFAIK, you can't listen to the audio prior to answering the call. (You can sometimes send audio prior to answering the call). So you can't tell if it is a fax or not. Personally, I presume you would need to bill your user for that 15 seconds, or else you will end up losing money. You answered the call, therefore the telco is charging you, if you don't charge your user, then you will lose. Of course, I could be wrong, but I doubt it :) I'd like to know how those 'home/soho' fax machines 'detect' an incoming fax and allow the inside phone to ring, and only pick up if it is a fax call..... Regards, Adam -- -- Adam Goryachev Website Managers Ph: +61 2 8304 0000 [EMAIL PROTECTED] Fax: +61 2 9345 4396 www.websitemanagers.com.au _______________________________________________ Asterisk-Users mailing list [email protected] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users _______________________________________________ Asterisk-Users mailing list [email protected] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
