Vertex Standard VXR-7000 Service Manual page 6

Operating Manual Reprint
LINE Interface Port
The VXR-7000 is provided with an 8-pin modular jack
for line interfacing applications. A Western Electric
lar-type RJ45 plug should be used to connect to this jack.
The LINE jack pin-out is shown below.
Note that there are both 4-line and 8-line types of modu-
lar plugs. If a 4-line modular plug is used, only the LINE
OUT and LINE IN connections will be made. An 8-line
plug is required to access all lines. In accordance with
standard telecommunications interface, the line connec-
tions on the LINE interface jack are impedance balanced,
and are described as follows.
Pins 1 & 2: [RX SQ(+), RX SQ(–)]
(max voltage: 20 V, max current: 7 mA)
An opto-isolator is provided to facilitate E (EAR) sig-
naling. The opto-isolator comes on when a signal ex-
ceeding the receiver squelch appears on the receiver
channel (with correct CTCSS tone or DCS code, if
enabled). The RX SQ(–) pin is the emitter, and RX
SQ(+) is the collector.
Pins 3 & 4: [LINE IN (Tx Line Audio)]
Analog signals between 300 and 3000 Hz supplied to
this pair are fed to the transmitter when the repeater is
set to the BASE mode (the REPEATER LED is turned
off) and keyed either by the TX KEY input signal (see
below), or by the EXT PTT signal on pin 12 of the
rear panel's ACC jack. Standard deviation is obtained
with a line level of –10 dBm.
Pins 5 & 6: [LINE OUT (Rx Line Audio)]
Receiver audio is available from this pair, subject to
internal CTCSS or DCS decode if the received signal
strength is above the squelch threshold.
As shipped from the factory, a 1-kHz receiver signal
with standard deviation gives –10 dBm on the line,
but this can be varied by VR4002 and S4001 (on the
repeater's CNTL Unit).
Pins 7 & 8 [ ( ),
(max voltage: 20 V, max current: 4 mA)
An opto-isolator is provided to facilitate M (MIC) sig-
naling. That is, a voltage presented to these pins turns
on the opto-isolator and keys the transmitter. The TX
KEY(+) pin is the anode of the opto-isolator, and RX
SQ(–) is the cathode of the opto-isolator.
LINE Jack
Modular Jack Pin Numbering
6
® modu-
( )]
Installation
Antenna Considerations
Repeater operation without a duplexer requires that two
antennas be installed, one for receiving and one for trans-
mitting, so that the receiving antenna does not absorb en-
ergy from the transmitting antenna. There are a number of
ways to do this, depending on the TX/RX frequency sepa-
ration, and on the locations available for antenna mount-
ing. If a duplexer is used, a single antenna suffices for
both transmitting and receiving. If using a reduced-size
duplexer, a six-cavity model (minimum) is recommended.
Vertex Standard recommends the use of the duplexer. For
further details, contact your Vertex Standard dealer.
Regardless of the above choice, it is of paramount impor-
tance that the antenna(s) be mounted as high and in the
clear as possible, preferably within line-of-sight to all re-
peater users. Furthermore, losses in the feedline(s) must
be minimized, so the feedline(s) should be high quality,
and as short as possible. If a long feedline is necessary,
use coaxial "hardline" cable to reduce losses.
Repeater antennas should have an impedance of 50 W at
the operating frequency. When separate receive and trans-
mit antennas are used, high-Q narrow-band types may
serve to minimize interaction. However, when a single
antenna is used with a duplexer, it should be a low-Q wide-
band type.
NEVER TRANSMIT WITHOUT HAVING A
TRANSMIT ANTENNA CONNECTED TO THE
TX ANTENNA JACK OF THE REPEATER.
AC Power Supply Voltage Selection
Each repeater is wired for a particular AC mains voltage
between 100 and 253 VAC. This should be indicated by a
label near the AC jack on the rear panel. If no label is
present, or if the AC voltage on the label is different from
the local AC line, check the wiring inside the Switching
Regulator Unit of the repeater, and change the connec-
tions (and label) if necessary, as shown next page.
Changing the AC input voltage wiring also requires chang-
ing the fuse on the FILTER Unit if the voltage is changed
from 100 VAC (100-127 VAC) to 200 VAC (207-253
VAC), or vice-versa. Use a 5-amp fuse for 100 VAC, or a
3-amp fuse for the 200 VAC.
VXR-7000 UHF Service Manual