Guardian G25AMK005, Technical Manual

Page: 29 / 85

G U A R D I A N V H F 1 1 0 W M O B I L E 2-19
PTT processing : In normal operation, a PTT switch closure causes Q2 to conduct, which in turn causes Q7 to
conduct. This signal is distributed to the rest of the radio as the PTT signal. When a DTMF button is depressed, the
transceiver automatically transmits this tone.
PTT lockout : To prevent transmission of DTMF tone during programming, a latch circuit is provided to lockout
PTT. When the ENTER button is pressed the PTT signals is disabled by a latches circuit. When the ESCAPE button
is pressed the lockout latch is reset. It is recommended to utilize the PTT condition lockout during programming the
PTT (light will stay off). This is done by pressing ENTER key and after that hold the PTT key depressed until
programming is done. To re-key the radio release PTT and key the radio once the radio is out of the programming
mode use the ESC key quit programming.
J1, 80-pin boat connection
J2, IDC, 20-pin audio
connection
J3, IDC, 20-pin audio
connection
J4, 20-pin display
connection
J5, RJ11, 8-pin MIC
and KLV connection
DTMF to keypad
interface
Programming PTT
disable
Volume selector
and on/off control
On/off controlled
3.3V regulator
LED
drivers/control
Channel, speaker
out, ABC switch
selectors
J6, 2-pin
speaker
connection
Figure 2-5: Interface Board