Configuring Internal Or External Clocking; Building The Null Modem Cable - Sun Microsystems Sun PCI High Speed User Manual

Configuring Internal or External
Clocking
To configure an RS-449 port to provide transmit clocking for itself as well as receive
clocking for the other end of the link, set the txc (transmit clock) and rxc (receive
clock) parameters in hsip_init to baud and rxc, respectively. For example, the
following hsip_init command sets the data rate of the first Sun HSI serial port to
9600 bps and sets the clocking as just described:
# hsip_init hihp0 9600 txc=baud rxc=rxc
You enter such a command at both ends of a link if both sides are supplying clocking.
In the situation in which you have Sun systems at both ends of a link and have one
system supplying clocking for both sides, on the system that is not supplying the
clocking, you enter:
# hsip_init hihp0 9600 txc=txc rxc=rxc

Building the Null Modem Cable

To build a null modem cable, you can configure your own cable or use a standard
cable with an adapter box.
Note – Be sure to use shielded, twisted pair wire when building a null modem cable.
If you decide to use an adapter box, be sure to obtain an adapter that allows you to
change the pin configurations. Pre-configured adapters generally do not work with
synchronous protocols because they do not handle clock signals correctly.
30 Sun PCI High Speed Quad Port Serial Interface Adapter User's Guide • May 2010