Sun Microsystems Interface Adapter - Manual (Page 49)

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A P P E N D I X
B
Null Modem Cable Requirements
A synchronous null modem cable is a specially configured cable that simulates
modems that are connected back-to-back. When the distance between the two host
systems is not great, you may be able to use a null modem cable instead of a
synchronous modem or a synchronous modem eliminator.
The maximum distance a null modem cable can work is determined by the
specification for your serial port interface.
There are two steps you must perform to use a null modem cable for machine
supplied clocking:
■ Run hsip_init (see “Configuring Internal or External Clocking” on page 30 ) so
that the Sun system, in the absence of a synchronous modem, supplies clocking
on the serial line.
■ Build or configure the cable for the null modem.
Note – You must run hsip_init each time you reboot your system.
The following topics are included in this appendix:
■ “Configuring Internal or External Clocking” on page 30
■ “Building the Null Modem Cable” on page 30