P/N 3100346 ISSUE 3
PAGE 8
<CHKSUM>
Optional two byte Message Block checksum (2 bytes). Refer to Section 4.0 for
Block checksum calculation and verification. If checksum is not desired, must pad
these two bytes with two ASCII zeros 00.
Unit Response: <STX><UA> 44 <TIME LEFT><ACK><ETX> <CHKSUM>
<UA>
Unit address characters (2 bytes). See Section 2.0, Messaging Format
<44>
Two byte ASCII Command 43 echoed back from the receiving unit (2 bytes).
<TIME LEFT>
Represents seconds left, in hexadecimal format, until the unit stops playing active
Tone/Message. Range 00-63 hex (2 bytes). The unit’s internal counter returns the
time remaining in seconds represented by a two byte hexadecimal value in the
above data field.
Note:
For non-timed events, the unit returns two ASCII zeros ‘00’.
<ACK>
Unit received a complete message and checksum characters are valid.
Note:
In the event that a bad checksum is calculated, by the receiving unit, it will
reply with a <NAK> character instead. The <NAK> character has a value of 15
hexadecimal.
<ETX>
The <ETX> character has a value of 3 hexadecimal and is required at the end of
every message (1 byte)
<CHKSUM>
Receiving unit calculates two-byte checksum and returns ASCII value. Refer to
Section 4.0 for Block checksum calculation and verification.
Example 1:
Prior to issuing Command 44, the master issues a 99 second timed sequence event
for Tone/Message 03 to play on unit address 1F.
Command:
<STX>1F0399A<ETX>00
9 seconds after issuing command from above, the master issues the “
Time
Remaining
” Command 44
Command: <STX>1F4400A<ETX>00 and the unit replies with the following message.
Reply:
<STX>1F445A<ACK><ETX>5E
Value 5A (90 decimal) is the hexadecimal representation of seconds left before the
timed sequence event completes and Tone/Message stops.
3.5
DEVICE TYPE COMMAND - 45
Send Format:
<STX><UA>45<00> <ZONE> <ETX> <CHKSUM>
<UA>
Unit address characters (2 bytes). See Section 2.0, Messaging Format
<45>
Two byte ASCII Command 45 denoting receiving unit’s Device type (2 bytes).
<00>
Two byte ASCII ‘00’ used as protocol padding (two byes)
<ZONE>
Programmable unit Zone issued by the master or controlling computer
Range ASCII A-D (1 byte).
<ETX>
The <ETX> character has a value of 3 hexadecimal and is required at the end of
every message (1 byte)
<CHKSUM>
Optional two byte Message Block checksum (2 bytes). Refer to Section 4.0 for
Block checksum calculation and verification. If checksum is not desired, must pad
these two bytes with two ASCII zeros 00.
Unit Response: <STX> <UA> <DEVICE TYPE> <vXX> <ETX> <CHKSUM>
<UA>
Unit address characters (2 bytes). See Section 2.0, Messaging Format
<45>
Two byte ASCII Command 45 echoed back from the receiving unit (2 bytes).
<DEVICE TYPE> Device type is an ASCII string transmitted by the receiving unit that defines the
unit family product code. For Millennium devices, the return ASCII string is “M-
485”. For Edward’s Visual devices, the return ASCII string is “S-485”.
<vXX>
Receiving Unit’s Firmware version and revision level.
<ETX>
The <ETX> character has a value of 3 hexadecimal and is required at the end of
every message (1 byte).
