AudioCodes Mediant 1000 User Manual page 84

Digital Mediant 1000
When MEGACO and MFC-R2 protocols share control of a channel, their timings are
synchronized so that MEGACO commands do not cause damage to the MFC-R2 protocol's
negotiation. For example, MFC-R2 protocol must work with the Echo Canceler in OFF state
or else Multiple Frequency (MF) is not received correctly. Thus, if MEGACO protocol
receives a command to open a channel with the Echo Canceler ON and MFC-R2 protocol's
negotiation is not yet finished, the entire negotiation could be damaged. To avoid this
problem, the MEGACO will not change the echo canceler state until the call was accepted
by the answering side.
The actual call should start only after the accept signal is finished. (See the call flow of call
start).
The application supports a special option called re-answer. In this option, the answering
side can put down the phone, and pick it up again. The phone close will result with the
'icas/cb' event, but if the phone is taken up again, the 'bcas/ans' event will be sent. The
timing of this action is defined by the MGC. It is the MGC responsibility to decide when the
call should be disconnected by sending the 'icas/cf' signal. (refer to the figures below for
the call flow of the call disconnect for the use of these signals and events).
User's Manual 84 Document # LTRT-66401