58
MDS 9810 Installation and Operation Guide
MDS 05-3301A01, Rev. C
Desensitization:
75 dB
Spurious:
70 dB minimum
Bandwidth:
25 kHz
Interference Ratio
(BER degraded by 10
-1
):
Co-channel:
–10 dB
Adjacent channel:
+30 dB
Two channels away:
+50 dB
Three channels away:
+60 dB
Time Required to Synchronize
with Master Radio:
Less than 13 seconds (typical)
8.2 RSSI Checks with a Voltmeter
As an alternative to the HHT method of measuring RSSI (see Antenna
Aiming on page 27), a dc voltmeter may be connected to Pin 21 of the
transceiver’s
DATA INTERFACE
connector.
Figure 28 shows the relationship between RSSI and the dc voltage at Pin
21.
NOTE:
RSSI Readings are not accurate for incoming signals stronger
than –50 dBm.)
Invisible place holder
Figure 28. RSSI vs. Vdc at Pin 21 of DATA INTERFACE Connector
8.3 Data Interface Connections (DB-25)
The
DATA INTERFACE
connector is used to connect the radio to an
external DTE data terminal that supports the EIA-232 format. The radio
supports data rates of 1200, 2400, 4800, 9600, 19200 and 38400 bps
(asynchronous data only).
The
DATA INTERFACE
connector mates with a standard DB-25 plug that
is available from many electronics parts distributors. Figure 29 shows
the layout of the
DATA INTERFACE
connector.Table 15 lists each pin on
the connector and describes its function.
2
2.5
3
3.5
4
–110
–90
–70
–50
+ DC VOLTS (PIN 21)
SIGNAL LEVEL (dBm)
4.5
5.0
