Consilium SELUX ST, Installation And Service Manual

Page: 40 / 180

SERIAL INTERFACE SPECIFICATION
2.5 Rev. E
NOTE 3
The AIS channel is indicated as either “A” or “B”. This channel indication is
relative to the operating
conditions of the AIS unit when the packet is received. This should be a null
field when the channel identification is
not provided. The VHF channel numbers for channels “A” and “B” are
obtained by using a “query” (see 7.3.4) of the
AIS unit for an ACA sentence.
NOTE 4
This field supports up to 60 valid characters. Under certain conditions, this
field may support up to a
maximum of 62 valid characters: 1) When the message can be transmitted
using a single sentence, the sequential
message identifier field is set to null allowing an additional valid character in
this encapsulated field. 2) When the
AIS channel field is set to null an additional valid character is allowed in this
encapsulated field. 3) The maximum
number of 62 valid characters is only possible when the conditions allow
both the sequential message identifier and
AIS channel fields is set to null.
NOTE 5
This cannot be a null field. See “x4” in 7.3.3.