User`s manual

Introduction
System Dependencies
Your 8500 series display terminal with the ADM is intended for use with the
AT&T 5ESS switch, or the AT&T DEFINITY Generic 2 or Generic 3
Communications Systems. You should be aware of which system your ADM is
connected to because some differences exist in the data transport capabilities of
each system.
The 5ESS switch supports both X.25 packet switched data communication and
circuit switched data communication. For X.25 packet switched data, the system
supports either dialed-up data calls (X.25 virtual circuit) or a permanent
connection (X.25 permanent virtual circuit). For circuit switched data, the system
supports only dialed-up data calls. Your ADM supports only one data call at a
time, either circuit or packet switched.
The DEFINITY Generic 2 and Generic 3 switches support circuit switched data
communication, but do not support X.25 packet switched data communication.
For circuit switched data, the system supports either dialed-up data calls or a
permanent switched connection.
Your ADM rate adapts circuit switched data calls onto 56 or 64 kbps channels.
This is true regardless of the asynchronous data rate of the EIA-232 interface.
Therefore communication circuit switched data directly between two ISDN
networks requires digital connectivity between the switching systems.
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