Modem Considerations - IBM 3270 Manual

Modem Considerations
All Countries except United Kingdom Date! Modem
• 3276 with an external modem attached to a switched or nonswitched line
United Kingdom Date! Modem
• 3276 with an external modem attached to a switched or nonswitched line
All Countries except U.S. and Canada
• 3276 with an integrated modem attached to a switched line with auto-answer
• 3276 with an integrated modem attached to a nonswitched line with SNBU and auto-
answer
All Countries except U.S., Canada, and Japan
• 3276 with an integrated modem attached to a nonswitched line
U.S. Only
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• 3276 with a Digital Data Service Adapter (DDSA) attached to the A. T. & T. Channel
Service Unit
All Countries
• 3276 with a Loop Adapter attached to a Loop
In countries served by IBM Americas/Far East (except Canada) and IBM Europe/Middle
East/Africa where it is permissible, your personnel (or contractor) will connect the
communication cable to the external modem, communication facilities termination, or
Loop Station connector. Where the local (country) regulations require a manufacturer's
representative to make the connection to the communication facility, the local IBM
branch office should be called for assistance.
W.rap Feature: Determine whether the modem permits data from the 3276 to be
wrapped under control of the 3276 or whether the modem has a switch to control the
wrap function. If the modem has the wrap capability and wrapping can be controlled
from the switch on the modem, it is recommended that this method be used.
Primary Line Speed/Secondary Line Speed Option: If the modem has a secondary line
speed option, determine whether this option can be controlled externally (by the 3276)
or by a switch on the modem. If the option can be controlled by a switch, it is
recommended that the switch be used to control this option rather than controlling it
externally by the 3276.
When the 3276 provides clocking, primary line speed/secondary line speed must be
controlled by a switch on the 3276. This switch is located on the operator panel drawer
to the right of the display screen. See the 3276 Switch Settings Form in Appendix D.
Switched Network Backup (SNBU) Feature: If the modem has this feature, determine
whether this feature can be controlled externally (by the 3276) or at the modem. It is
recommended that this feature be controlled by the 3276 by setting the SNBU/Non-
switched Line switch to SNBU. The switch is located on the operator panel drawer to the
right of the display screen. See the 3276 Switch Settings Form in Appendix D.
Note: In the U.S. and Canada a switched network attachment requires the use of a
protective device. This must be ordered from an original equipment manufacturer (OEM)
communication equipment supplier and installed separately.
*
Trademark of American Telephone & Telegraph Co.
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