Sun Microsystems Interface Adapter manual Null Modem Cable Requirements

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

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