звук (разьем) на материнской плате Intel D945GCLF
 

подскажите для чего используется желтій разьем на плате, подписан как audio имеет 10 контактов. можно ли к нему подключить экодер регулятор громкости?

Нет. Энкодер к нему не подключишь. Это "Front panel audio header". Т.е. линейный выход 2-х фронтальных каналов и ещё обычно вход микрофона с его питанием. Распиновку именно этого разъема, честно говоря, не знаю.

вот фото

Энкодера к нему не подключить.

Front Panel I/O Connectivity Design Guide
22
􀀒 NOTE
Motherboards that have the foot print for a front panel header, but depopulate the front panel
audio header must have 0 ohm resistors as options to connect the FP_OUT and FP_RETURN
signals. These resistors must be installed when the header is depopulated to insure audio is routed
to the back panel.
2.3.5 Intel® High Definition Audio
The Intel® High Definition Audio (Intel® HD Audio) analog front panel header design lets OEMs
and integrators place audio functionality on the front panel of a PC system via a cabled up front
panel dongle. Intel® HD Audio analog front panel dongles can support up to two analog audio
jacks, each of which signals user connection, or disconnection, to the operating system via the
SENSE_SEND signal. The signals for this header are defined in Table 7 and the physical header
pinout is shown in Figure 4.

Table 7. Intel® HD Audio Front Panel Analog Header Signal Names
Pin Signal Name Description
1 PORT 1L Analog Port 1 - Left channel (Microphone)
2 GND Ground
3 PORT 1R Analog Port 1 - Right channel (Microphone)
4 PRESENCE# Active low signal that signals BIOS that an Intel® HD Audio dongle is connected
to the analog header. PRESENCE# = 0 when an Intel® HD Audio dongle is
connected.
5 PORT 2R Analog Port 2 - Right channel (Headphone)
6 SENSE1_RETURN Jack detection return for front panel (JACK1)
7 SENSE_SEND Jack detection sense line from the Intel® HD Audio CODEC jack detection
resistor network
8 KEY Connector Key
9 PORT 2L Analog Port 2 - Left channel (Headphone)
10 SENSE2_RETURN Jack detection return for front panel (JACK2)

дальше так

Figure 4.
Intel® HD Audio - Analog Front Panel Header
Manufacturer's Part Number: Wieson* Electronic 2100C888-042 (or equivalent)

2.3.5.1 Intel® HD Audio CODEC Connections
In general, the CODEC ports selected for front panel use are connected to the Intel® HD Audio
header via series coupling capacitors C1 through C4. The resistors labeled Rbias are required if the
front panel jacks are required to support microphone functionality. Note that Figure 5 shows two
Vref output per CODEC port. The number of VREF outputs per PORT is a CODEC product
specific. Designers should consult their CODEC vendor’s datasheet for detailed information VREF
implementation, the details of the jack detection network, and selection of coupling capacitors.

Front Panel I/O Connectivity Design Guide

и последнее
Figure 5. Intel® HD Audio Front Panel Analog Header Motherboard Schematic
2.3.5.1.1 Dongle Presence Detection
The PRESENCE# signal is used to inform BIOS that an Intel® HD Audio dongle is connect to the
motherboard. This signal should be wired to a system GPI and BIOS should poll the GPI to check
for the presence of the Intel® HD Audio dongle in the system during POST. Nominal motherboard
pullup value of 10 k is required on this signal.
2.3.5.1.2 Jack Detection
Jack detection is accomplished with the use of the jack detection resistors Rjd_port1 and Rjd_port2.
The value of these resistors depends on which CODEC ports are tied to the Intel® HD Audio analog
header ports. Motherboard designers should consult the Intel® HD Audio specification for more
information on the assignment of these values for a give codec port.
2.3.5.2 Intel® HD Audio Front Panel Connections
Figure 6 shows a Intel® HD Audio front panel dongle implementation and a Intel® HD Audio front
panel analog header schematic. The front panel dongle consists of JACK1 and JACK2, and their
Front Panel Legacy I/O
25
associated signal pins, connected directly to their respective pins on the dongle stake pin header.
The SENSE_SEND signal is split and routed through the PORT1 and PORT2 isolated switches.
The other contact of each isolated switch, are routed to their respective sense return signals,
SENSE1_RETURN and SENSE2_RETURN. This functionality, together with the Rjd_PORT1
and Rjd_PORT2 resistors on the motherboard as shown in Figure 5, informs the audio driver of
jack insertion or removal, which is necessary for dynamic re-taking of the front panel jacks.
Finally, a 1 k pulldown is required on the PRESENCE# pin to signal BIOS that the Intel® HD
Audio front panel dongle is connected to the system.

особенно в последнем варианте подключения. что такое Normally Open
Isolated Switch

нормально-разомкнутый контакт, т.е. что бы система думала что ты воткнул во фронтальную панель наушники, то тебе нужно этот контакт замкнуть.

спасибо теперь понял.