I have an IBM RS6000 and am using a Lantronix Secure Console Server or Multiport Device Server as a console server. I have no problem logging into my routers and other servers, but I cannot get a login on the RS6000. A null modem cable from a PC works fine. What could might cause this?

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Many RS6000 console ports require that CD be held high. Since many null modem cables jumper CD and DSR, this requirement is met. The Lantronix 200.2069A adapter jumpers DSR and CD so that the RS6000 sees an asserted signal on its CD pin:

             Cable                     Adapter
RJ45       (Straight)          RJ45(200.2069A) DB-9   Signal
RTS 1     1-------------1       1---------------8     CTS
DTR 2     2-------------2       2----------|----6     DSR
                                           |----1     CD
TXD 3     3-------------3       3---------------2     RXD
SGD 4     4-------------4       4-----|---------5     Signal Ground
SGD 5     5-------------5       5-----|         5     Signal Ground
RXD 6     6-------------6       6---------------3     TXD
DSR 7     7-------------7       7---------------4     DTR
CTS 8     8-------------8       8---------------7     RTS



If you prefer to build your own "three-wire" adapter for XON/XOFF or NO Flow Control use this wiring:



             Cable                         Adapter
RJ45       (Straight)          RJ45    (User supplied)       DB-9     Signal
RTS 1                                                8----|  CTS
                                                          |
DTR 2                                                6--| |  DSR
                                                     1--| |  CD
TXD 3     3-------------3       3--------------------2  | |  RXD
SGD 4     4-------------4       4------------|-------5  | |  Signal Ground
SGD 5     5-------------5       5------------|          | |  
RXD 6     6-------------6       6--------------------3  | |  TXD
DSR 7                                                4--| |  DTR
                                                          |
CTS 8                                                7----|  RTS

                                                          ^jumper 1,4&6 and 7,8

In both cases the asserted signal on DTR is seen by CD on the RS6000 so that it will accept the connection.

*Note - This article does not apply to the discontinued SCS820 or SCS1620.

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[Originally Published On: 08/30/2000 09:47 AM]