Compaq Armada 7400 Reference Manual page 108

If you are running Windows 95 or Windows 98 to
establish an infrared link:
Be sure the infrared ports on both computers are turned on and
facing each other at a distance no greater than 1.5 feet (about
0.5 meter).
Avoid moving the infrared ports away from each other during
data transmission.
Avoid interference from remote control units, such as wireless
headphones or audio devices, pointed at the infrared ports.
Avoid direct sunlight, fluorescent light, or flashing
incandescent light close to the infrared ports.
Keep the path between the infrared ports free of any objects
that might interfere with data transmission.
Do not point one of the ports more than 30 degrees (plus or
minus 15 degrees off the center line) away from the infrared port
of the device you are connecting with.