SATELLINE-EASy Pro 35W
User Guide v.1.4
26
7.4
Forward Error Correction
Forward Error Correction, FEC-function is switched ON (or OFF) by using the
Programming
Mode
. When activated, the FEC-function will cause the SATELLINE-EASy Pro 35W to
automatically add additional error correction information, which increases the amount of
transmitted data by 30 %. It is used by the receiving radio modem to correct erroneous bits - as
long as the ratio of correct and erroneous bits is reasonable.
Error correction improves the reliability of data transfer via the radio interface especially in
unfavourable conditions. FEC-function should be used when link distances are long and/or if
there are many disturbances in the radio channels used. The use of the FEC-function will,
however decrease the data transfer throughput of data by about 30 %. The list of exact delays
when using FEC-function, are introduced in appendix B.
To switch the FEC-function ON in the
Programming Mode,
select:
1) Error correction ON
7.5
Error checking
When the error checking is switched on, the radio modem will add a checksum to the transmitted
data. When the data is received, the checksums are verified before data is forwarded to the serial
port. There are two different options for error checking that can be accessed in the Additional
setup menu in the Programming Mode:
2) Error check
6) Full CRC16 check
Error check
checks data partially while data is received.
Full CRC16 check
function adds two checksum characters at the end of the user data message. At
the reception end the receiver receives first the whole package and if the checksum matches the
data message is forwarded to the serial port. If
Full CRC16 check
is selected it must be set ON for
all radio modems in the same network. Otherwise the checksum characters appear at the end of
user message on the serial port.
7.6
Dual radio function, separate RX/TX-frequencies
The SATELLINE-EASy Pro 35W can transmit (TX-frequency) and receive (RX-frequency) on separate
frequencies. Separate frequencies can be set within the whole tuning range. The frequencies can
be set in the display menu, in the programming mode or by the Configuration Manager.
NOTE!
All radio modems, which are to communicate with each other, must have the same setting for
FEC (ON or OFF). If the transmitting radio modem and the receiving radio modem has
different settings, data will not be received correctly.
