TK-2200
11
Fig. 11 Control system
CIRCUIT DESCRIPTION
Channel selector
CPU
IC405
SCAN
EN4
EN3
EN2
EN1
47
48
49
50
PTT
PTT
SW
LOCK
27
74
75
SW1
SW2
EN5
46
X2
XOUT
IC405
Q407
Q408
Hi: OFF
LOW: ON
BSHIFT
Fig. 8 Frequency shift circuit
Fig. 9 Memory circuit
IC405
CPU
IC406
EEPROM
SB
R404
R406
88
IC405
CPU
Fig. 10 Low battery warning
2) Memory Circuit
Memory circuit consists of the CPU (IC405) and an EEPROM
(IC406). An EEPROM has a
capacity of 64k bits that contains
the transceiver control program for the CPU and data such
as transceiver channels and operating features.
3) Low Battery Warning
The battery voltage is checked using by the microprocessor.
The transceiver generates a warning tone when it falls below
the warning voltage shown in the table.
(1) The red LED blinks when the battery voltage falls below
the voltage (1) shown in the table during transmission.
Note:
The transceiver checks the battery voltage during reception
even when, in the FPU, the Battery Warning status function
is set to “On TX” (default setting).
However, the LED does not blink during reception. During
transmission, the LED blinks to generate the warning tone
of a low battery voltage.
(2) The transceiver immediately stops transmission when
the battery voltage falls below the voltage (2) shown in
the table. A message tone beeps while the PTT switch
is released.
7. Control System
Keys and channel selector circuit.
The signal from the keys and channel selector are directly
input to the microprocessor, as shown in fig. 11.
Ni-MH Battery
(1)
6.2 [V]
(2)
5.9 [V]