Mediant 2000 SIP User’s Manual

8. Gateway Capabilities Description

If the call transfer fails, the gateway either plays a busy tone (if the destination client to whom the call is transferred is busy) or it plays a reorder tone (for all other reasons). The tone is played for 10 seconds (TimeForReorderTone=10) towards the CallPilot.

Usually, the CallPilot detects these Call Progress Tones and either disconnects the call or unholds it using double hook-flash signaling. If the CallPilot doesn’t react to these tones, the gateway releases the call, and idle the CAS A/B bit state.

If the call transfer fails (if user B is busy, for instance), detection of a double hook-flash from the CAS side unholds the call and retrieves the original call (using reINVITE).

If the call transfer succeeds, the gateway plays a Ringback tone for ‘TimeForReorder’ (about 10 seconds) and tears down the call. To play the Ringback tone set ‘PlayRBToneonXfer=1’.

Disabling the B-channel – If DTMF digits aren’t received from the CallPilot after applying a

dial tone to the CAS side (usually for 30 seconds, i.e., the duration of a dial tone), the gateway’s B-channel converts to ‘Block’ state. During ‘Block’ state, the channel is put out of service and is not used for IP Tel calls. To enable the B-channel, apply CAS A/B idle state (0,1) from the CallPilot side.

8.13.3 DTMF Configuration

To use out of band SIP INFO messages to relay DTMF digits, add the following parameters to the ini file.

IsDTMFUsed = 1

OutOfBandDTMFFormat = 1

RxDTMFOption = 0

To use RFC 2833 DTMF relay, add the following parameters to the ini file.

IsDTMFUsed = 0

TxDTMFOption = 4

RxDTMFOption = 3

DTMFTransportType = 3

For detailed information on DTMF transport modes, refer to Secion 8.5 on page 143.

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Nortel Networks TP-1610 SIP user manual Dtmf Configuration