Datum bc632D, User Manual

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DIGITAL TIME TRANSMISSION PROTOCOL
Datum Inc bc632D Wall Mount LED Display (Rev A) A-7
The remainder of the message is the same as in the previous section.
The message must be transmitted within the one second period following the on-time mark.
Note
: If the receiving device remains at 9600 BPS, it may detect the 8 microsecond pulse as a
start pulse and interpret this as a character, or it may ignore it completely, depending on the
serial receiver. The reference pulse may also be thought of as a valid asynchronous character
$FF at 125K Baud.
A.7.5 MULTIPLEX TIME
The multiplex time protocol is similar to the digital time protocol. It is intended for an installation of
several displays which may have to show different times. It uses the same physical wiring configuration.
The format of the multiplexed time messages is:
CHNx YY+DDD HH:MM:SS.
:::::: <CR> <LF>
Where:
"CHN" is all capitals.
"x " is an ASCII character specifying the channel, followed by a space.
"
:::::: " is six ASCII hexadecimal characters representing the time tag of the
beginning of the stop bit of the first "C" in the "CHN" message. The
unit of time is a half-microsecond (see "Time Tags" below). It is
followed by a carriage return ($0D) and a line feed ($0A).
The other fields are the same as above.
The message must be transmitted within the one second period following the on-time mark.