Microphone (Hm-36); Ptt Switch - Icom IC-718 Instruction Manual

2
PANEL DESCRIPTION
n Microphone (HM-36)
q UP/DOWN SWITCHES [UP]/[DN]
Change the selected readout frequency or memory
channel.
• Continuous pushing changes the frequency or memory
channel number continuously.
• The [UP]/[DN] switch can simulate a key paddle.
Preset in the CW PADDL in initial set mode. (p. 31)
• MICROPHONE CONNECTOR
(Front view)
q Microphone input
w +8 V DC output
e Frequency up/down
• HM-36 SCHEMATIC DIAGRAM
8
q
w
i Main readout AF output
(varies with [AF]/[BAL])
u GND
(Microphone ground)
y GND (PTT ground)
t PTT
r Main readout squelch switch
MICROPHONE
+
10µ
4700p
MIC
ELEMENT
DOWN
PTT
RECEIVE
TRANSMIT
w PTT SWITCH
Push and hold to transmit; release to receive.
[MIC]
FUNCTION
PIN NO.
+8 V DC output
w
Frequency up
e
Frequency down
Squelch open
r
Squelch closed
CAUTION:
can damage the internal 8 V regulator.
MICROPHONE CABLE MICROPHONE PLUG
2k
+
0.33µ
4700p
q
w
UP
e
470
DESCRIPTION
Max. 10 mA
Ground
Ground through 470 Ω
"LOW" level
"HIGH" level
DO NOT short pin 2 to ground as this
u
i y
t
r