TITLE    : 8-wire modem cable for the 128-port RAN
OS LEVEL : None 
DATE     : 06/04/99
VERSION  : 1.0

----------------------------------------------------------------------------
         

            RJ45 Connector           13   DB-25 Connector     1     
                                      |                       |
           +-----------+            .-|-----------------------|-.       
           |           |            | o o o o o o o o o o o o o |      
         +-+           +-+           \ o o o o o o o o o o o o /      
         |               |            -|---------------------|-        
         |_______________|             25                   14         
          8 7 6 5 4 3 2 1
 

      
              Wiring Diagram
    +--------------------------------+   * The physical location of DSR and
    | RJ45                DB-25      |     CD may be swapped with the ALTPIN
    |                                |     parameter when enabled using the
    |                     22    RI   |     stty-cmxa commar.
    | 1  ---------------  6     DSR* |
    | 2  ---------------  4     RTS  |
    | 3  ---------------  Shell GND  |
    | 4  ---------------  2     TxD  |
    | 5  ---------------  3     RxD  |
    | 6  ---------------  7     GND  |
    | 7  ---------------  5     CTS  |
    | 8  ---------------  20    DTR  |
    |                     8     CD*  |
    +--------------------------------+


ALTPIN Modem Wiring for RJ-45 Cabling

The 10-pin RJ-45 plugs is not the predominant cabling subsystem and may be 
difficult to obtain in the retail market. The AIX TTY subsystem provides an
optional feature called ALTPIN, which swaps the logical functions of DSR 
(Data Set Ready) with DCD (Data Carrier Detect) for a port. When ALTPIN is 
enabled, DCD becomes available on pin 1 of an 8-pin RJ-45 connector 
(equivalent to pin 2 of a 10-pin connector).