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Each filter list has a switchable type: WHITE or BLACK. A message is passed thru the WHITE filter
if it contains a record matched with a message. And the reverse for BLACK. In the factory settings, all
filter lists are empty and are of BLACK type, so all messages are passed through filters. To change the type
of the active filter, use the TYPE command. For example:
TYPE WHITE
0183 filters contain 3-char NMEA 0183 sentence formatters. According the standard, a NMEA 0183
sentence start with a $ or ! symbol, followed by two-character talker ID and 3-char sentence formatter.
These elements are followed by data fields (after the comma). The sentence is finished by a check sum
after the * (asterisk) symbol.
The Device uses 3-char sentence formatters only for filtering. The following sentences matches to GLL
and VDM records (sentence formatters):
$GPGLL,4146.5894,N,07029.6952,W,173412.02,A*02
!AIVDM,1,1,,B,ENk`smq71h@@@@@@@@@@@@@@@@@=MeR6<7rpP00003vf400,4*5F
Other filters actually contain pairs of 29-bit message identifiers and a mask. The identifier is compared
by processing the NMEA 2000 message identifier and the second value (mask) defines the comparison
concerning which bits are significant.
The identifier contains a PGN (Parameter Group Number, described in NMEA 2000 Standard)
and a source device address. PGN and ADDR keywords may be used to modify these lists more easy.
You can use decimal and hexadecimal numbers (which start with a 0x prefix).
Multiple parameters may be passed to a command. The following examples add and remove all added
records (note that right column syntax is differ):
FILTER GLOBAL_RX
ADD PGN 130310 130311
REMOVE PGN 130310
REMOVE 0x1FD0700 0x1FFFF00
ADD ADDR 0x10
REMOVE ADDR 16
FILTER 0183_TX
ADD XDR GLL VDO
REMOVE XDR
REMOVE GLL VDO