Checking the Physical Layer

First of all make sure that all of your modem and power cables are in good working order, and that they are all plugged-in, switched on, and tightly seated. Then carry out loopback tests. Finally, check the line status.

If you are using the onboard serial port of a SPARCstation, the most thorough hardware test you can do is to use syncloop. If you are using the SUN HSI card, the most thorough hardware test you can do is to use hsi_loop. If you are using another manufacturer's card, refer to their documentation.

To check the line status, use the syncstat or hsi_stat command to observe the line over periods of ten seconds.

Checking a High Speed Interface

If you are using a high speed interface, use the hsi_loop command to perform a loopback test to check the following components of your communications link:

• Software configuration

• CPU-to-card communication

• Correct operation of the serial port

• EIA-449 or EIA-232 ports and cables

• Local and remote modems

• Transmission line

If you see errors in the output, contact your local technical support for help in interpreting them.

Checking the Serial Port Line Status

The syncstat command monitors traffic that uses the onboard serial port or the serial port on the SCiiExpress-X card.

If you see output packets but no input packets, then either the remote system is not initialized or the line is not properly connected to the remote system. If you see input packets with CRC errors, the transmission medium is causing errors. If you see neither input nor output packets, then the Solstice X.25 protocol module was not successfully initialized. Try restarting the device.

Checking High Speed Interface Line Status

The hsi_stat command monitors traffic over a high speed interface. You must log in as root, or become superuser, to run hsi_stat.

If you see output packets but no input packets, then either the remote system is not initialized or the line is not properly connected to the remote system. If you see input packets with CRC errors, the transmission medium is causing errors. If you see neither input nor output packets, then the Solstice X.25 protocol module was not successfully initialized. Try restarting the device.