Files
dahdi-linux/drivers
Shaun Ruffell 5f7ebe98da dahdi: Only watch transitions of ABIT when using E&M signalling.
This resolves an issue with a Glenayre GL3000 Paging Terminal with v8.000
software. The Glenayre would change both A and B bits to signal on/off hook
states, but there were a couple of milliseconds between when those bits changed.
This resulted in DAHDI generating an on-hook event to Asterisk before generating
the off-hook event and therefore Asterisk terminated the call prematurely.

Looking the A and B bits before this patch:

Asterisk (AB)   Glenayre (AB)
00              00                 Both sides on-hook
11              00                 Asterisk goes off hook to sieze line.
11              01                 Glenayre starts going-offhook. On-hook event
                                     sent to Asterisk from drivers since bits
                                     changed but ABIT was still 0.
11              11                 Glenayre finishes going off-hook. Off-hook
                                     event sent to Asterisk since ABIT changed
                                     from 0 to 1.
00              11                 Asterisk, processes on-hook event and goes
                                     on-hook itself to release line.
00              00                 Glenayre releases line. Call fails.

After this patch:

Asterisk (AB)   Glenayre (AB)
00              00                 Both sides on-hook
11              00                 Asterisk initiates call
11              01                 Glenayre starts handling call. No event is
                                     sent to Asterisk since only ABIT is checked.
11              11                 Glanayre finishes going off-hook. Call
                                     proceeds normally.

Internal-Issue-ID: DAHDI-1009
Signed-off-by: Shaun Ruffell <sruffell@digium.com>
Signed-off-by: Russ Meyerriecks <rmeyerriecks@digium.com>
2012-12-11 10:27:57 -06:00
..