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Support for ISDN Busy Out Channel with PPL Event Request

Description

This feature allows the host to busy out the channel though a PPL Event Request message for the 4ESS variant of ISDN in the BSS component.

Busy Out B Channel

When the host sends the Event Request, the CSP does not disconnect the call. Instead it busies out the B channel. The host will receive a positive ACK. The host sends another Event Request to bring that channel back into service for subsequent calls.

Configuration Byte to Send Event Indication

The configuration byte 0x03 in the BSS component allows this component to send the Event Indication to the host reporting the B channel state.

Event Indication Sent

When the B channel is busied out, the BSS Component reports that to the host with PPL Event Indication 0x02.

Refer to L3 B Channel Control (0x000B) for the details of the PPL information involved with this feature.

See Programmable Protocol Language.
See Integrated Services Digital Network.
Bearer channel, 64Kbps (ISDN) The channel that carries the actual payload (as opposed to D-channels, which carry signaling data that helps route the payload).
Positive acknowledgment to a message
A condition that, when met, drives a state machine from one state to another. A condition that drives a Component out of its current state by invoking an associated primitive.