Interface Adapter User's Guide

Appendix B Null Modem Cable Requirements 33
FIGURE B-2 illustrates a synchronous null modem cable that enables you to connect to
to another system, Sun or nonSun, using the RS-449 interface. The Sun system
supplies both the transmit and receive clocks for the other system. Note that this
null modem cable is not symmetrical.
FIGURE B-2 Null Modem Cable –Sun System Supplies Clocking for Both Sides
TxD (4,22)
RxD (6,24)
RTS (7,25)
CTS (9,27)
DSR (11,29)
SG (19)
DCD (13,31)
RxC (8,26)
DTR (12,30)
TxC (17,35)
Sun workstation
TxD (4,22)
RxD (6,24)
RTS (7,25)
CTS (9,27)
DSR (11,29)
SG (19)
DCD (13,31)
TxCI (5,23)
RxC (8,26)
DTR (12,30)
Sun System or
other device
that supplies clocking