Operating Instructions Part 2

10 OEM Series™ I/O Guide MDS 05-3624A01, Rev. B
Table 2 shows the losses that occur when using various lengths and
types of cable in the 900 MHz band. Regardless of the type of cable
used, it should be kept as short as possible to minimize signal loss.
2.4 Power Connection
The transceiver can be operated from any well-filtered 10 to 16 Vdc
power source. The power supply must be capable of providing at least 2
Amperes if 5 watt output is planned from the transceiver. Supply the
power to the power connector (see Figure 5 on Page 6).
Do not apply power to the radio through Pin 18 of the DB-25
Interface connector. This pin does not provide over-current input
protection, and is intended only as an auxiliary output for powering
a low-current (1.0 Amp max.) device, such as an RTU.
NOTE: The radio is designed for use in negative ground systems only.
Conservation (Sleep Mode)
In some installations, such as at solar-powered sites, it may be necessary
to keep the transceiver’s power consumption to an absolute minimum.
This can be accomplished by configuring the data device (RTU, PLC,
etc.) to ground Pin 12 of the
DATA INTERFACE connector, which removes
power from the radio. When the ground is removed, the radio is ready
to operate within 75 milliseconds.
2.5 Data Interface Connections
The transceiver’s DATA INTERFACE connector is configured as a DCE
(modem) and is normally connected to an EIA-232 device. The
transceiver supports over-the-air asynchronous data rates up to
19200 bps. Refer to Figure 10 and Table 3 for a detailed description of
each pin on the
DATA INTERFACE connector.
Table 2. Length vs. Loss in Coaxial Cables at 900 MHz
Cable Type
3 Meters
(10 Feet)
15 Meters
(50 Feet)
30 Meters
(100 Feet)
150 Meters
(500 Feet)
RG-8A/U 0.85 dB 4.27 dB 8.54 dB 42.70 dB
1/2 inch HELIAX
0.23 dB 1.15 dB 2.29 dB 11.45 dB
7/8 inch HELIAX
0.13 dB 0.64 dB 1.28 dB 6.40 dB
1-1/4 inch HELIAX
0.10 dB 0.48 dB 0.95 dB 4.75 dB
1-5/8 inch HELIAX
0.08 dB 0.40 dB 0.80 dB 4.00 dB
CAUTION
POSSIBLE
EQUIPMENT
DAMAGE