Reference Guide for the Model XM128 ISDN Digital Modem
In some areas, however, it is very expensive to get additional subscriber numbers. The subaddress, which is transferred transparently by the ISDN network between the calling user and the addressed user, can be used for the same purpose as the MSN. Because the Model XM128 modem is highly integrated and multifunctional, it can be thought of as a black box that contains 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, determined by the bit 5 of S119 as follows:
•S119.5=0 for number treated as the MSN (default)
•S119.5=1 for number treated as the subaddress
The factory defaults for these numbers are unassigned. If an incoming setup message is offered with addressing information (in other words, the appropriate part of the called party number or the called party subaddress), this address is compared with the MSN/subaddress numbers assigned by the AT&ZIn=xxxx... commands. The call is accepted using the specific protocol if the assigned number of this protocol matches the received called party number or called party subaddress.
Note: Two phone number strings are said to be matched if their least significant n digits 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 (for example, the destination address
Best-effort Call Answering
If some numbers have been set using the &ZI command (as can be seen by the AT&ZI? command) and they are not matched with the address of the incoming call, the Model XM128 modem, by default, ignores the call because it may be intended for other devices that share the same S/T interface (S0 bus) with the modem.
Advanced ISDN |
