[asterisk-r2] How to configuration for Polarity Reversal for DTMF R2

[Moises Silva]

2011/10/6 Piyawit Khumkrong <piyawit at aistelebiz.com>:
> I have a problem with R2(DTMF) connection the solution is 1 port to Telco 1
> port to NEC
>
> so the problem is NEC can't detect answered call to billing system and can't
> transfer the call from operators
>
> then NEC engineer said "that is the problem from polarity reversal" can
> anyone tell me

Polarity reversal is used in analog lines (FXS lines) to signal
answer, not in CAS systems. In R2, the answer is signaled using CAS
bits and is currently being done. You need to ask your NEC technician
why is their system not able to detect the CAS bit changes that we
send to signal "Answer"


Moises Silva
Senior Software Engineer, Software Development Manager
Sangoma Technologies Inc. | 100 Renfrew Drive, Suite 100, Markham ON
L3R 9R6 Canada
t. 1 905 474 1990 x128 | e. moy at sangoma.com