Ambiguity Resolution Switch For Voice Calls (Non-Data); Multi-Auto-Answering Of Data Calls; Data Call Indication - ZyXEL Communications ACCESSING INTERNET & INTRANET omni series User Manual

If you want the TA to answer inbound calls as often as possible, you
can set the best-effort call answering bit as follows:
S119.3=0 - Answer calls only when numbers match (by default).
S119.3=1 - Best effort call answering.

Ambiguity Resolution Switch for Voice Calls (non-data)

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
will be delivered to the proper destination. Sometimes, ambiguity of
address matching may exist. This may happen if the &ZI numbers of
the various protocols are either unassigned or not matched. 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 (omni.net).
The AT&Ln command sets the address ambiguity resolution flag:

Multi-Auto-Answering of Data Calls

For an ISDN data call, if the TA can exclusively determine the
protocol to be used by means of the information conveyed by the
SETUP message (for DSS1, these include the Bearer-Capability,
Low-Layer-Compatibility, or High-Layer-Compatibility information
elements; for 1TR6, these include the Service Indicator as well as the
Additional Octet of Service Indicator), then the indicated protocol
will be used. Otherwise, the Multi-Auto answering process will be
invoked. The omni can monitor the B channel signal sent by the
calling site.
The data call can be identified by the TA to be X.75, V.110, V.120,
or PPP Async-to-Sync, conversion and MPPP.

Data Call Indication

Data calls are accepted the same way as in any TA. When alerted, the
omni will send the first RING message to the DTE with a format as
follows:
RING <CR><LF>
Advanced ISDN Call Control 87