multiple distinct terminals. Each of these "internal terminals" can be assigned one ISDN number using the AT&ZIn=xxxx... command.
The number assigned by AT&ZIn=xxxx... can be interpreted as either the MSN or the subaddress. This is determined by the bit 5 of
S119 as follows:
∙S119.5=0 - the number is treated as the MSN (default).
∙S119.5=1 - the number is treated as the subaddress.
The factory default for these numbers are unassigned. If an incoming SETUP message is offered with addressing information (e.g. the appropriate part of the called party number or the called party subaddress), this address will be compared with the MSN/subaddress numbers assigned by the AT&ZIn=xxxx... commands. The call will be accepted using the specific protocol if the assigned number of this protocol matches with the received called party number or called party subaddress.
ONOTE: Two phone number strings are said to be matched if their least significant "n" digit(s) are identical, where "n" is the number of digits of the shorter string. Usually one digit is enough to distinguish the various protocols.
Answering a Call for 1TR6
If an incoming SETUP message is offered with addressing information (i.e. the destination address
Best-effort Call Answering
If some numbers have been set using &ZI command (as can be seen by the AT&ZI? command) and they are not matched with the address of the incoming call, the TA will, by default, ignore the call as it may be intended for other devices that share the same S/T interface (S0 bus) with the TA.
86 Advanced ISDN Call Control
