User`s guide

42 DC 900-1340I
BSC Programmer’s Guide
The following features allow greater programming flexibility:
• Multiple levels of interface routines
• Automatic dialing of SADL, AT, and V.25bis autodial modems
• Trace session for recording protocol activity
• Control session for control and monitoring of multiple links
• Automatic text blocking and deblocking
The multipoint (poll-select) protocol operation feature is not supported by the Proto-
gate BSC 2780/3780 product.
2.4 BSC 2780/3780 Access Modes
Each BSC 2780/3780 session on a link can be set to one of the following access modes:
Manager, Read, Control, or Trace. Multiple sessions can be active on any one link, but
only one of each access mode is allowed per link. The access mode is defined in the DLI
configuration file (Chapter 7) using the client-related “
mode” parameter (described in
the Freeway Data Link Interface Reference Guide).
The valid BSC 2780/3780 access modes are defined in Tabl e 2–3 . Ta ble 2 –4 shows the
required access modes for various operations.
Caution
If a Manager session is using blocking I/O (with a Read session on
the same link), the unacknowledged writes from the Safe Store
Acknowledgment and Disconnect commands could eventually
prohibit further writes to Freeway. Therefore, Protogate recom-
mends that these two commands be issued only from the Read ses-
sion.