2.28. gc_SetChanState( )

When power is initially applied, all bearer channels (B channels) are placed in the In Service state.

Note: In some protocols, the D channel may need to be activated before the B channels can be placed in the In Service state.

For some protocols, when a channel is placed in an Out of Service state, all incoming and outgoing call requests are rejected.

The gc_SetChanState( ) function can be used to place a B channel in an Out of Service state to avoid unnecessarily rejecting calls. Valid states for the chanstate parameter are GCLS_INSERVICE (0), GCLS_MAINTENANCE (1) and GCLS_OUT_OF_SERVICE (2).

Note: This feature may not be available in some countries.

Cautions

• E-1 ISDN protocols do not support any message for putting B channels in an In Service or Out of Service state, therefore, the gc_SetChanState( ) function cannot be used when using E-1 ISDN protocols to avoid receiving incoming calls on some channels. An E-1 application that is not ready to, or does not want to, receive incoming calls on some B channels should not issue the gc_WaitCall( ) function on the respective channels or it should issue the gc_ResetLineDev( ) function on the respective channels to cancel the waitcall operation.
• The gc_SetChanState( ) function affects only the link between the calling process and the device. Other processes and devices are not affected.
• The gc_SetChanState( ) is not supported for E-1 ISDN or NTT PRI protocols, or for any BRI protocols.

When using DM3 boards, when a B channel is placed in service, a SERVICE message may be transmitted, depending on the value of the CHP SetParm 0x1312 parameter in the CONFIG file. The CHP SetParm 0x1312 parameter controls the sending of the SERVICE message when a B channel is placed in service. For more information on the CONFIG file settings, see the configuration information for DM3 products provided with the system release software.

Click here to contact Telecom Support Resources