If the ISDN physical circuit desired by the AU does not exist between the terminal and the AU, the procedures for physical channel establishment described in the following subclauses apply.
The format of the SETUP message sent by the network to the user is in accordance with 3.1.
The Bearer capability information element included in the SETUP message shall be encoded with:
- information transfer capability set to either:
a) unrestricted digital information; or
b) restricted digital information;
- transfer mode set to circuit mode;
- information rate set to 64 kbit/s.
The Channel identification information element shall be encoded according to Table 6-2.
The B-channel connection to the called user shall be established by the network using the signalling procedures described in 5.2. The call is offered by sending the SETUP message on a point-to-point data link or on the broadcast data link.
The user responds to the SETUP as defined in 5.
Network requested channel and user response, Incoming access from an AU
Channel indicated in the SETUP message network to user direction |
Allowable network response (user-network) |
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Information channel selection |
Preferred or exclusive |
D-channel indicator (Note 1) |
|
Bi |
Exclusive |
No |
Bi |
Bi |
Preferred |
No |
Bi, Bi' (Note 2) |
Bi Indicated (idle) B-channel Bi' Any other idle B-channel (not permitted for broadcast call offering) NOTES 1. D-channel indicator shall be encoded "0" to indicate No and "1" to indicate Yes. 2. This encoding is not used for broadcast call offering. 3. All other encodings are invalid. |
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