IBM System/34 Maintenance Manual page 480

,r "
,
'----""
'-.-)
31-200 ADAPTER CARD
--
The data communications adapter cards in A-A2J2 and
A-A2K2 are the common interface between System/34
and all modems. Each card has four switches; set them
as instructed in Figure 31-19.
'--___ _rJLL-___ ---JJLL-___
-----I)~L__
_ _ _
_r
A·A2J2 (line 1); A·A2K2 (line 2)
Switch Condition Meaning
1 On Continuous carrier (the 'request to send' line is always on).
Note: Set this switch off if continuous carrier is needed with the 2400 BPS modem with SNBU
and attach a jumper from B·A1 M2G02 to B·A1T2B09 (line 1), or jumper from B·A2M2G02 to
B·A2T2B09 (line 2).
Off Not continuous carrier (set off for OOSA and for switched networks)
2 On For EIA, 2400 BPS modem, and for enable rate select.
Off
For OOSA, 1200 BPS modem, and for disable rate select.
3 On Not N RZI coding
Off NRZI coding used
Note: The customer can use BSC and/or SOLC on the same communication line. Therefore, the
following information is important to the setting of the N RZI switch (switch 3) on the adapter
card:
•
The NRZI switch setting must match the option chosen in the configuration for diagnostics
to work correctly.
•
If the customer is operating with only BSC or with DOSA, select not NRZI (switch 3 is set on).
•
BSC microcode disables the NRZI function regardless of the switch setting.
•
Only SOLC uses NRZI but the selection of NRZI depends on the following:
- If the customer is operating with SOLC (or with SOLC and with BSC on the same communi·
cation line), the switch setting and the configuration record must be set for SOLC operation.
operation.
-
The NRZI switch setting depends on the remote device and on the modem being used. For
SOLC, all data terminal equipment communicating with each other must select the same
coding option (NRZI or not NRZI). Contact your IBM marketing representative for identi·
fication of those modems that have pattern sensitive synchronization problems, and to
determine which coding option should be used. When PTT mandatory modems are used in
World Trade, refer to the IBM World Trade Signal Converter Handbook, ZZ19-6066. This
manual will help determine wh.ich co,ding optipn should be used.
4 On Device address and interrupt request bit. If only one communication line is installed on the
system, set switch 4 on. If switch 4 is on, the device address 80 and the interrupt request bit 0
(bit 0
=
OBI 0) are used by the adapter.
Off
If switch 4 is off, the device address 20 and the interrupt request bit 2 (bit 2
=
OBI 2) are used
by the adapter.
Note: If two communication lines are installed, one adapter must use address 80 (switch on)
and the other adapter must use address 20 (switch off). If one of the lines operates at a speed
. greater than 4800 bps, it should use address 80 (switch on); the other line should use address
20 (switch off). If a 1255 is installed, always set line 1 to use address 80 (switch on).
Figure 31-19. Data Communications Adapter Card
'31·200
Data Communications 21
•