HP LaserJet 4 Service Manual - Page 435

Infrared Port Not Responding Table B-21 Solutions for Infrared Not Responding Situation The connection cannot be established or the transmission seems to be taking longer than usual. Solution Make sure the device you are using is IrDA-compliant; look for an IrDA symbol on the device or refer to the manual for the device for IrDA specifications. Make sure that the operating system on your computer includes an IR driver and your application uses a HP LaserJet 5/5M/5N compatible printer driver. Make sure you have positioned the device within the range of operation and that no objects, such as a finger, paper, books, or bright light, are interfering with the connection. Also make sure the two IR ports are clean (free from dirt and grease.) Bright light of any kind (sunlight, incandescent light, fluorescent light, or light from an infrared remote control, such as those used for TVs and VCRs) shining directly into one of the IR ports may cause interference. Position the device closer to the printer's IR pod. LaserJet 5/5M/5N Printer B-41