Guys, we all know about debug isdn q931 output message, I've 4 doubts in that. (which are in highlighted form in the attached snapshot)
& i = 0x80 (Line 12)
Please check the attached snapshot for your reference.
Thank you in advance.
Below is the required information:-
1). channel id is composed of Bearer capability and the channel (i.e. slot occupied for the call)
for e.g in your case Bearer Capability is = 0x8090A3 and channel is 31 which int turns into 0xA9839F
Here, A398 value is interchanged from the bearer capability and 9F (80+1F) is the hex value of channel no 31 (hex=1F)
2). pd stands for protocol discriminator which means that value is used to distinguish messages for user-network call control from other messages.
pd=8 for Q.931 user-network call control messages
pd=9 for Q.2931 user-network call control messages
3). Progress Ind i = 80 means it indicates that tones and announcements are available for that particular call.
various other progress indicaiton is as below:-
4). calling party & called party information is as below:
· 80 the router
· 81 the private network near the local user (possibly a local private branch exchange [PBX])
· 82 the public network near the local user (local telco switch)
· 83 the transit network (in the ISDN cloud)
· 84 the public network near the remote user (remote telco switch)
· 85 the private the network near the remote user (possibly a remote PBX)
· 87 the international network
· 8A a network beyond the internetworking point
Hi Nishant, thanks for your quick response.
Channel ID is composed of Bearer capability + Channel
Bearer Cap -> 0x8090A3 represents Voice/Speech call (G711 - A-law)
For e.g. In our case Bearer Capability is = 0x8090A3 (which represent that G711 A Law codec is being used) and channel is 31 which int turns into 0xA9839F (how it got turn into this value 0xA9839F, is that a hexa. addition or sort of something)
A398 value is interchanged from the bearer capability and 9F (80+1F) is the hex value of channel no 31 (hex=1F) ?
Decoding these values require understanding of Q.931:
That is really helpful Paolo, Thanks