Reference Guide for the Model XM128 ISDN Digital Modem
If you want the Model XM128 modem to answer inbound calls as often as possible, you can set the best-effort call answering bit as follows:
•S119.3=0 for Answering call only when number matched (by d efault)
•S119.3=1 for best effort call answering
Ambiguity Resolution Switch for Voice Calls
For a voice or voice-band data call, if the &ZI number assignment can tell which of the analog adapters is being addressed, then the call is delivered to the proper destination. Sometimes, however, ambiguity of address matching may exist. This ambiguity may happen if the &ZI numbers of the various protocols are either unassigned or not matched or the address information is absent in the incoming setup message. In this case, users may wish to set the priority of answering a call by the analog adapter PHONE 1 or the analog adapter PHONE 2.
The AT&Ln command sets the address ambiguity resolution flag:
•AT&L0
The analog adapter 1 has the higher priority to answer a voice or voice-band-data call. If the analog adapter 1 is busy, the call is routed to the analog adapter PHONE 2.
•AT&L1
The analog adapter 2 has the higher priority to answer a voice or voice-band-data call. If the analog adapter 2 is busy, the call is routed to the analog adapter PHONE 1.
Multi-Auto-Answering of Data Calls
For an ISDN data call, if the Model XM128 modem can exclusively determine the protocol to be used by means of the information conveyed by the setup message (for DSS1, this information includes the bearer capability, low-layer compatibility, or high-layer compatibility information elements; for 1TR6, it includes the service indicator as well as the Additional Octet of Service Indicator), then the indicated protocol is used. Otherwise, the Multi-Auto Answering process is invoked. The Model XM128 modem can monitor the B channel signal sent by the calling site.
The data call can be identified by the Model XM128 modem as X.75, V.110, V.120, or PPP Async-to-Sync conversion and MPPP.
