5.7 C-CPU Board (05P0729)/C-IF Board (05P0730)
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5.7.2 C-IF Board (05P0730)
C-IF board consists of microphone amplifier, audio control circuit, AF amplifier and
PTT and HOOK signal detectors. The board receives AF signal, –10 dBm/600 Ω from
the transceiver unit as “LINE IN” signal. U6 sets AF output level to the loudspeaker.
The AF signal or LINE IN signal is also input to U3 on C-CPU board as SQ SIG. This
signal is used to generate MUTE signal according to SQ FRQ setting in system setting
menu. The MUTE signal controls external speaker (EXT SP). The AF line of the
handset is not controlled by SQ signal.
Fig.5.7.2 Block diagram of C-IF board
Table 5.7.3 Input/output level
Input/output level of C-IF board
Port
Input Output
Remarks
MIC
-10 dBm/600Ω -10 dBm/600Ω
For the condenser
microphone, HS2001
HANDSET
SP
-10 dBm/600Ω
-10 dBm/600Ω
(Ear SP:2.5mW/150Ω)
MIC
-46 dBm/600 Ω -10 dBm/600 Ω
For the dynamic
microphone,
HSC-701K-20B
HANDSET
/MIC
SP
-10 dBm/600Ω Ear SP:2.5mW/200Ω
Note)
The control unit provides two handset connection ports, [HANDSET]: HS2001 and
[HANDSET/MIC]: HSC-701K-20B. Do not use these ports at a time. Hook and PTT
lines on two handsets are connected in parallel.
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