Hardware Reference
In-Depth Information
Table 4.51 Telephony Connector
Table 4.52 ATAPI-Style Line In Connector
Note
Some boards have a board-mounted piezo speaker. It is enabled by placing a jumper over
pins3and4,routingthespeaker outputtotheboard-mounted speaker.Removing thejumper
enables a conventional speaker to be plugged in.
Most modern motherboards have three or four fan connectors for use with the processor
fan, rear chassis fan, front chassis fan, and voltage regulator (power) fan (see
Table 4.53
).
They generally use the same 3-pin connector, with the third pin providing a tachometer
signal for optional speed monitoring. If the motherboard is capable of monitoring the fan
speed, it can sound an alarm when the fans begin to slow down due to bearing failure
or wear. The alarm sound can vary, but it normally comes from the internal speaker and
might be an ambulance siren-type sound.
Table 4.53 Fan Power Connectors
Caution
Do not place a jumper on this connector; serious board damage will result if the 12V is shor-
ted to ground.
