4. Operation 39 
 Alert instance, 1 to 999999
(11) Revision counter, 1 to 99 
 Escalation counter, 0 to 9
 Alert text
 
ALC,xx,xx,xx,x.x,aaa,x.x,x.x,x.x,……,aaa,x.x,x.x,x.x*hh <CR><LF> 
(1) (2) (3)    (4)  (5) (6) (7)    (8)   (5) (6) (7)    (8)    (9)   
Total number of sentences for this message, 01 to 99
Sentence number, 01 to 99
 Sequential message identifier, 00 to 99
 Number of alert entries
 Manufacturer mnemonic code
 Alert identifier
 Alert instance
 Revision counter
 Checksum
 
SDARC, hhmnss.ss, aaa, x.x, x.x, c*hh<CR><LF> 
(1)   (2)   (3)  (4)  (5)(6) 
Release time
Alert specifically defined by the manufacturer
 Alert ID
 Alert Instance, 1 to 999999
 Rejected alert command
 Checksum
 
$--ACN,hhmmss.ss,aaa,x.x,x.x,c,a*hh <CR><LF>
 
(2)   (2) (3) (4)  (5)(6)(7)  
Time
Manufacturer mnemonic code
 Alert Identifier
 Alert Instance, 1 to 999999
 Alert command, A, Q, O or S
 Sentence status flag
 Checksum
 
SDHBT, x.x, A, x*hh<CR><LF> 
(1)  (2) (3) (4)   
Repetition cycle setting
Equipment status
 Sequence number
 Checksum