Vertex VXR-5000 User Manual page 16

VXR-SOOO
17.
TONE OFF
Logic Input (Active Low)
This input is internally pulled up to 5-V
DC. When pulled low by an external de-
vice, it disables the internal CTCSS de-
coder (if enabled). The internal CTCSS
encoder section is not affected by this in-
put. Use this input when channel monitor-
ing with squelch action is required (e.g.
tone monitor function). Voltage in excess
of 5 V on this pin may damage the CPU on
the repeater CNTL-1 Unit.
18. TX Logic Ouput (Active Low)
This open-collector logic output is pulled
low when the transmitter is activated. It
can sink approx. 100 mAo The signal on
this pin is always true when the transmit-
ter is on. It is intended to be used where an
"ON-AIR" indication is required.
19.
AUDIO MUTE
Logic Input (Active Low)
This input is internally pulled up to 5-V
DC. When pulled low by an external de-
vice, it disables receiver output to pins 5
&
6 of the modular
LINE
jack. In the RE-
PEATER mode, the repeat audio is not af-
fected by signals on this pin. Avoid voltage
in excess of 5 V on this pin or internal
damage to the CPU on the repeater CNTL-
1 Unit may result.
20.
SQ LOW
Logic Input (Active Low)
This input is internally pulled up to 5-V
DC. When pulled low by an external de-
vice it selects the low squelch mode. In low
squelch mode, the hysteresis between
squelch open and closed is only 3 dB (in-
stead of the normal 6 dB). The squelch
closing level is unchanged.
The absolute squelch closing level is set by
VR4001 on the RX Unit. For example, if the
squelch on the RX Unit has been set to
open at -110 dBm in normal mode, then
1-14
with the
sa
LOW pin grounded, the
squelch will now open at about -113 dBm.
In either case, the squelch will close at -116
dBm. Avoid voltage in excess of 5 V on this
pin, which could damage the CPU on the
repeater CNTL-1 Unit.
21,22 & 23.
REMOTE
DO,
DI
&
D2
Logic Inputs
(Active Low)
These inputs are internally pulled up to
5-V DC. When pulled low by an external
device, they select one of the eight pre-pro-
grammed repeater operating channels.
The logic truth table below shows the com-
binations for selecting all 8 channels.
In the truth table, "I" represents no con-
nection, and "0" represents a ground con-
nection on the pin.
The channel selection logic is not inhibited
while the transmitter is keyed: the repeater
will change frequency when instructed,
even while transmitting.
Avoid voltage in excess of 5 V on these
pins or internal damage to the CPU on the
repeater CNTL-1 Unit may result.
VXR-5000 Channel Access
(DO-D2, pins 21,22 & 23)
CH
02 01 DO
1
1 1 1
2
1 1 0
3
1 0 1
4
1 0 0
5
0 1 1
6
0
1
0
7 0 0
1
8 0 0 0
24 & 25.
RST
+ &
RST-
Logic Inputs
An opto-isolated RESET input is pro-
vided between pins 24 and 25. A voltage of
between 3 and 15 V resets the repeater
microprocessor.