Transparent Data Transmission
Radio Protocol Support
18
SRL-35 Operator’s Manual P/N: 1003224-01
Example of a short data block:
00 This is a testline of SATELLINE-3AS radio modem
Long Data Block Test
Long data blocks consists of character strings, which are repeated without breaks for a fifty (50) second
time period. After a ten (10) second break the test transmission is started again.
The Long block data test can be used for measuring TX output power, Standing Wave Ratio (SWR) of the
antenna system or received signal strength at RX stations. Using the Long Block Test requires running the
modem in radio compatibility mode SATELLINE-3AS.
Example of a long data block:
00 This is a long testline of SATELLINE-3AS radio modem
The strength of the received signal can be monitored using the LCD Display of the receiving radio modem.
Latency in PCC Transparent Mode
In the PCC Transparent protocol mode (Option 1 and Option 2) the whole message is first read from the
serial port and after that it will be framed and transmitted over the radio.
The end of the message is detected when there is a pause in data coming from the serial port.
The symbol rates for the Pacific Crest 4FSK (Option1) are:
•
19200 bps on 25 kHz channel
•
9600 bps on 12.5 kHz channel
The symbol rates for the Pacific Crest GMSK (Option2) are:
•
9600 bps on 25 kHz channel
•
4800 bps on 12.5 kHz channel
The actual raw data rate is approximately 2/3 of the symbol rate.
Transmission Delays using Pacific Crest 4FSK on 25 kHz channel
The table below presents the typical latency vs. the size of the message. The delays are measured from
the end of transmitted data to the end of received data on the serial interface.
Table 14. Number of bytes sent
Bps 1 10 100 500
1200 77 ms 159 ms 971 ms 4590 ms
4800 48 ms 68 ms 317 ms 1438 ms
9600 43 ms 52 ms 209 ms 912 ms
19200 40 ms 45 ms 154 ms 650 ms
38400 39 ms 41 ms 127 ms 519 ms
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