Kenwood TKR-740, Service Manual

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TKR-740
12
OPERATING FEATURES
14. Digital Pager
The TKR-740 can be used as a digital paging transmitter by
using the Digital Pager inputs on the rear panel. These inputs
accept the logical 0 or 1 (0 V or 5 V) from the external paging
encoder, producing a +4.0 kHz carrier shift in response to a 0
and a -4.0 kHz in response to a 1. If Digital Paging Input function
is enabled, the TKR-740 accepts the external encoder
’ s digital
signal on AUX In 3 and its PTT on AUX In 2 (active low).
15. Time Out Timer
The Time Out Timer function determines the period of time
users can continuously transmit. When the selected period
expires, the transmission is inhibited.
16. Repeat Hold Time
The Repeat Hold Timer (hang timer) function is used to
prevent the repeater from being repeatedly keyed and unkeyed
in response to short message traffic. When a mobile
transceiver unkeys, the repeater
’ s Hold Timer allows the
repeater to continue transmitting for a brief period while waiting
for a responding end user. If no valid QT/DQT is detected within
the Hold Timer period, the transmitter is allowed to unkey.
This function determines the period of time that the transmitter
is allowed to remain keyed after the loss of a valid QT/DQT
received signal.
17. Take Over
Take Over function is used to disable the remote wireline
control of the repeater. When Take Over function is enable,
the AUX Inputs and outputs, remote audio inputs and outputs,
External PTT, External Monitor, Remote PTT and TXD2/RXD2
serial data lines are disabled. All AUX Input functions assigned
to any AUX Input remain in current state. However Remote
PTT, External PTT and External Monitor become a
“ Off ” state.
18. Test Tone
The Test Tone is a single-frequency audio sine wave and is
turned On and Off by toggling Test Tone On/Off functions.
The transmitter can be modulated without a local mic by using
the test tone. When Test Tone On function is executed and
any PTT is activated, the TKR-740 transmits the test tone with
mic mute and also routes the test tone to Remote RA port.
19. AUX Input and Output
There are 7 programmable AUX I/O Ports 1-7(pins 6-12) on
the rear 12 pin REMT I/O connector and 3 programmable AUX
Input Ports 1-3 (pins 4-6) and 6 programmable AUX Output
ports (pins 20-25) on the rear 25 pin D-Sub connector. The 7
programmable AUX I/O pins are primarily intended for remote
control interfaces. Each AUX I/O Port can be set for AUX Input,
AUX Output or remote Channel Select types.
The AUX Input port can be set execute a single input
function or a set of up to three functions when the port is
activated. If the port type for an AUX I/O Ports 1-7 is set for
“ AUX Input ” , it will also appear AUX Input window for function
programming. The input logic is fixed as active low.
The AUX Output port can be set execute a single output
function. If the port type for an AUX I/O Ports 1-7 is set for
“ AUX Output ” it will also appear AUX Output window for
function programming. The Output logic of AUX Output can
be set as either active High or active Low by the Logic Type
function. Active High outputs a High (5V) when the
programmed condition becomes valid; active Low outputs a
Low (0V) when the condition becomes valid.
20. Channel Select
AUX I/O Ports 1-5 (1 or all 5) can each be set for “ Channel
Select ” providing up to 32 channel selection capability. These
are 1 to 5 bit Binary Coded Decimal (BCD) inputs. AUX I/O 1 is
a least significant bit. When all of AUX I/O ports 1-5 is set to
Channel Select,
“ 11111 ” input (LSB on the right side) signifies
the Channel 1 and “ 11110 ” input signifies the Channel 2. When
the Channel Select function is set to any AUX I/O Ports, The
Channel
‘ X ’ function (Channel Up, Channel Down, Channel 1,
etc.) can not be set to the AUX Input ports, but can be set to
the PF Keys. Normally the channel control is controlled by the
Channel Select function. If the Take Over function is executed,
the channel control is disabled to be controlled by the Channel
Select and enabled to be controlled by the PF Keys.
21. Start Up
When the TKR-740 is first turned on or is reset, up to 3
functions pre-programmed into the Start Up function are
executed in sequence.
22. Optional Board
The TKR-740 can be installed as a optional scrambler board.
Scrambler codes between 1 and 16 are available per channel.
If the scrambler board is not to be used (although it is installed),
set the parameter to
“ Off ” . When any Scrambler code is set
up and Scrambler On function is executed, the scrambler board
is activated.