IBM 6C4 - Manual (Page 205)

IBM 7852-400 DIP Switch Settings
If you are using a 7852-400 modem to enable service processor communications, for
proper operation, the dual inline package (DIP) switches must be set according to the
following table:
Switch Position Function
1 Up Force DTR
2 Up Flow Control &E4
3 Down Result Codes Enabled
4 Down Modem Emulation Disabled
5 Up Auto Answer Enabled
6 Up Maximum Throughput Enabled
7 Up RTS Normal Functions
8 Down Enable Command Mode
9 Down Remote Digital Loopback Test Enabled
10 Up Dial-Up Line Enabled
11 *Up AT Responses Enabled (Extended Responses Disabled)
12 *Down Asynchronous Operation
13 Up 28.8KB Line Speed
14 Up
15 Up CD and DSR Normal Functions
16 Up 2-Wire Leased Line Enabled
* Only switches 11 and 12 are changed from the factory default settings.
Xon/Xoff Modems
Some early modems assume software flow control (Xon/Xoff) between the computer
and the modem. Modems with this design send extra characters during and after the
transmitted data. The service processor cannot accept these extra characters. If your
configuration includes such a modem, your functional results may be unpredictable.
The sample modem configuration files included in this appendix do not support these
modems, so custom configuration files are necessary. Anchor Automation 2400E is an
example of such a modem.
If you experience unexplainable performance problems that may be due to Xon/Xoff
characters, it is recommended that you upgrade your modem.
Appendix F. Modem Configurations 187