Power; Cables; Modems; Replacing A 3275 With A 3276 - IBM 3270 Manual

Power
Cables
Modems
Replacing a 3275 with a 3276
10
If
the configuration of the 3276, of its ports, and of its attached units differs in any way
from the configuration of the replaced 3271, its ports, and attached units, the device
(program) addresses are affected. For example, the device addresses may be affected
when:
• More than one 3276 is required to replace a 3271.
• The 3276 is located at the site of a unit other than the 3277 that was attached to 3271
port 0.
The 3276 is not available with a 208/230 volt power option for the U.S. and Canada. If
the 3271 uses these voltages, you may have to arrange to have the power and power
receptacles changed. Refer to IBM 3270 Information Display System: Installation
Manual - Physical Planning, GA27-2787, for power requirements.
The least amount of change to existing cables occurs when the 3276 is placed at the
location of the replaced 3271, because all cluster cables originate from that location. The
3271 is a control unit, whereas the 3276 is both a control unit and a display station that
may replace both the 3271 and one of the attached 3277s.
It
may be necessary,
therefore, to locate the 3276 at the site of one of the replaced 3277s, because the
location of the repiaced 3271 may not be suitable for an operator. When this is the case,
the cluster cables have to be rerouted, replaced, or extended to accommodate the new
cluster configuration. In addition, it is recommended that the existing device cables
(coaxial cables between the 3271 and its attached units) be marked as described under
"3276 Device Cables."
The communication cable that connects the 3271 to its modem cannot be used with the
3276. A new communication cable is delivered with the 3 276. The standard cable length
is 6.1 metres (20 feet); optional cable lengths of 3.1 metres (10 feet), 9.1 metres (30
feet), and 12.2 metres (40 feet) may be specified. If the 3276 has the loop adapter, the
standard cable length is 1.8 metres (6 feet); optional cable length of 4.3 metres (14
feet) may be specified.
Note: All the 3271 cluster cables must be connected/disconnected by an IBM service
representative, because the 32 71 and its attached units do not have customer access areas.
When the 3276 is located at the site of one of the replaced 3277s rather than at the site
of the replaced 3271, it may be necessary to relocate the modem, because it can be no
more than 12.2 metres (40 feet) from the 3276.
If more than one 3276 is required to replace a 3271, additional modems may be required.
When a 3275 is replaced by a 3276, the 3276 can use the external modem (if applicable)
and the device address that were used with the 3275. However, the communication cable
that connects the 3275 to its modem or communication facility termination cannot be
used with the 3276. A new communication cable is delivered with the 3276. The standard
cable length is 6.1 metres (20 feet); optional cable lengths of 3.1 metres (10 feet), 9.1
metres (30 feet), and 12.2 metres (40 feet) may be specified.