HP LaserJet 4 Service Manual - Page 434

On HP Laser-Jet printers, a self-test page will be initiated by the test. If the "TEST" LED goes out and the "PASS" LED fails to light, the printer's IR port is not functioning correctly; check the operator's instructions included with the IR test tool. To test the host computer: 1 Place the test tool on a table in front of the PC's IR port. 2 Press the "computer Test button. The test tool will sequence the LEDs. If the "PASS" LED light, the test was successful, indicating that communication with the printer's IR port is functioning normally. If the "TEST" LED goes out and the "PASS" LED fails to light, the host's IR port is not functioning correctly. B-40 LaserJet 5/5M/5N Printer