Telemetry Module MT-021 User Manual

After reception of SMS message, internal application tries to parse SMS text and execute
command enclosed in it. Parsing process generates new message text, which is send
back to user (if module is allowed to, either by configuration or by presence/absence of
'$' sign).
Commands are formatted as follows:
#[prefix.]symbol[=value]
where:
prefix defines data representation and register count
symbol defines register address and register space being accessed
value defines data to be written to register (s)
Prefix is optional; when not present, data is interpreted according to preset defaults.
Basic read command:
#HR0
When module receives and parses the SMS message containing this command,
command string will be replaced with value of register 0 read from holding registers
space, noted in decimal format, and this value will be put in SMS sent back to user.
Answer to this command sent back will be:
>10
where 10 is value read from holding register 0.
If received SMS contains any other characters than correctly formatted commands,
these characters will be copied unaltered to message being sent back. This allows user
to freely compose text of return message and include register values together with
some informational text. For example, if user sends containing:
Voice call was #IR12 seconds long
then module will answer with:
>Voice call was 15 seconds long
where 15 is a value read from input register 12.
It should be noted that answer from module begins with '>' sign - it means that this SMS
was generated by module. If module receives SMS beginning with '>', such message
will be ignored (not parsed). This prevents endless "looping" of messages in case they
are being exchanged between modules
Writing to register is archived by expanding basic command with '=' sign and value that
should be written:
#HR20=2
User should be aware that writing is allowed only to holding register space.
When module receives SMS with write command, it executes the command and sends
back value written. For example, sending to module SMS with text:
#HR1=1234
80