I Microphone (Hm-103); Technical Information - Icom IC-703 Instruction Manual

I Microphone (HM-103)

DN
q
UP/DOWN SWITCHES [UP]/[DN]
Change the operating frequency.
• Push and hold to change the frequency continuously.
• Tuning step is 50 Hz when no TS indicator appears.

TECHNICAL INFORMATION

• MICROPHONE CONNECTOR
Rear panel view
8 7 6 5 4 3 2 1
q +8 V DC output
w Frequency up/down
e AF output
r PTT
t GND (Microphone ground)
y Microphone input
u GND
i Squelch switch
• HM-103 SCHEMATIC DIAGRAM
MICROPHONE
+
10µ
MIC
ELEMENT
PTT
RECEIVE
TRANSMIT
q
LOCK
UP
OFF ON
w
PIN NO.
1
2
8
2k
MICROPHONE
CABLE
4700p
0.33µ
+
4700p
2.2k
LOCK DOWN UP
470
e
w
LOCK SWITCH [LOCK]
Locks the [UP]/[DN] switches.
e
PTT SWITCH [PTT]
Push and hold to transmit; release to receive.
FUNCTION
+8 V DC output
Frequency up
Frequency down
Squelch open
Squelch closed
CAUTION:
DO NOT short pin 1 to ground as
this can damage the internal 8 V regulator.
MICROPHONE PLUG
1 2345678
PANEL DESCRIPTION
DESCRIPTION
Max. 10 mA
Ground
Ground through 470 Ω
"LOW" level
"HIGH" level
1
1
10