SATELLINE-3AS
User Guide, Version 2.3
24
To toggle the
Priority
setting in the programming menu, select:
1) Priority RX / TX
If the Repeater Function has been set on (see chapter 6.1), priority setting is automatically
switched to RX mode.
3.4 Error correction
Another new feature of the SATELLINE-3AS is the addition of an error correction mode called the
FEC-method (F
Forward E
Error C
Correction). FEC-function is switched ON (or OFF) by using the
Programming Mode
. When activated, the FEC-function will cause the SATELLINE-3AS 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 %. For a listing of exact
delays introduced by using FEC-function, see Chapters 15.1 and 15.2.
To switch the FEC-function ON in the
Programming Mode,
select:
1) Error correction ON
3.5 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. Erroneous data will be rejected.
Switching the error checking ON in the
Programming Mode,
select:
2) Error check ON
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 have
different settings, data will not be received correctly.
