When X.25 calls are to be offered on the B-channels without channel negotiation, the procedures described in 5.2 using the messages of 3.2 apply with the following exceptions:
a) The procedures for overlap receiving specified in 5.2.4 do not apply.
b) The procedures for receipt of CALL PROCEEDING and ALERTING specified in 5.2.5.2 apply with the following exception:
- The receipt of an ALERTING message shall not cause the network to send a corresponding ALERTING message to the calling user.
c) The procedures for call failure specified in 5.2.5.4 apply with the following remark:
- The network clears the incoming X.25 virtual call towards the calling X.25 DTE using the appropriate cause from Table 6-5.
d) The procedures for notification of interworking at the terminating interface specified in 5.2.6 apply with the following exceptions:
- The case of the call entering an ISDN environment during call establishment is not applicable.
- In the case of a call leaving the ISDN environment within the called user's premises, no notification is sent to the calling party.
- The case of in-band information/patterns is not applicable.
e) The procedures for active indication specified in 5.2.8 apply with the following exception:
- The network shall not initiate procedures to send a CONNECT message towards the calling user.
f) The procedures for user notification specified in 5.9 do not apply.
Where an established B-channel connection is to be used, the incoming call packet will be delivered in accordance with 6.3.
Where a new B-channel connection is to be established, the identity of the selected user will be associated with the Connection Endpoint Suffix (CES) from which the first CONNECT message has been received.