This is more an isdn question than an asterisk specific one, but is there any end to end signalling channel available during call setup? Eg if AParty dials BParty, can any information be conveyed (in both directions preferably, and in addition to CLI[PR]) before the call is answered? The only way I can think of doing this is for the AParty to use CLIP to present a different number to the BParty, and for the BParty to terminate the call while ringing after a certain time (the time taken to terminate forms the information from B to A). Thanks James
On Wed, Mar 15, 2006 at 02:01:50PM +1100, James Harper wrote:> This is more an isdn question than an asterisk specific one, but is > there any end to end signalling channel available during call setup? Eg > if AParty dials BParty, can any information be conveyed (in both > directions preferably, and in addition to CLI[PR]) before the call is > answered? >There is not such thing like A to B signaling, your phone/pbx is sending signaling messages to your provider pstn switch not to BParty.> The only way I can think of doing this is for the AParty to use CLIP to > present a different number to the BParty, and for the BParty to > terminate the call while ringing after a certain time (the time taken to > terminate forms the information from B to A). >On some E1/T1 , you can spoof callerid , everything depends on your provider. /pch -- Dyslexia bug unpatched since 1977 ... exploit has been leaked to the underground.
On Wed, 2006-03-15 at 14:01 +1100, James Harper wrote:> This is more an isdn question than an asterisk specific one, but is > there any end to end signalling channel available during call setup? Eg > if AParty dials BParty, can any information be conveyed (in both > directions preferably, and in addition to CLI[PR]) before the call is > answered?The USER-USER information element of Q.931 might do the trick, but support for that is still disabled in Asterisk 1.2.5 (look for SUPPORT_USERUSER in chan_zap.c). Maybe it works with one of the dedicated isdn channel modules. -- Dr. Michael Neuhauser phone: +43 1 789 08 49 - 30 Firmix Software GmbH fax: +43 1 789 08 49 - 55 Vienna/Austria/Europe email: mike@firmix.at Embedded Linux Development and Services http://www.firmix.at/