LG MG210 Service Manual page 40

Head set Jack Interface
EAR-MIC
Close to ABB
C243 0.1u
HSMICP
C245 4.7u
HSO
(1608)
C246
NA
When ear-mic set or head set plug is inserted into the receptacle, JACK_DETECT signal level which is
input of ADIN1 in ABB is changed. If hook button is pushed for a second to make a call, then
HOOK_DETECT signal which is input of ADIN4 in ABB goes GND level. Also call end has same
mechanism by pushing hook button on the Ear- microphone strap.
Ordinarily detection of pushing hook button is established by signal de-bouncing for about 20ms.
HSMICBIAS
1K R222
HOOK_DETECT
C235
47p
C240
C244
39p
10p L200 100nH
R226
L202
R225 120 C247 C248
100nH
1K
10p 27p
Figure 20. Ear-Jack interface
- 39 -
3. H/W Circuit Description
Close to Ear-jack
V_IO
R218 0
C231 C232
4.7u 10p
R219
(1608)
10K
C233
10u
R220 R221
(1608)
5.6K 47K
C241 C242
CN200
47p 10p 2
L201 100nH
4
3
1
L203 100nH 5
C249 C250
47p 10p
R227
33K
C251
27p
JACK_DETECT