Send identification command (al!)
Sensor identifiers are requested by issuing command aI!. The reply is defined by the sensor manufacturer but usually includes the sensor address, SDI-12 version, manufacturer name, and sensor model information. Serial number or other sensor-specific information may also be included. Source: SDI-12: A Serial-Digital Interface Standard for Microprocessor-Based Sensors (see References).
Command: aI!
Response: allccccccccmmmmmmvvvxxx...xx<CR><LF>
Where
a = sensor address
ll = SDI-12 version number (indicates compatibility)
cccccccc = eight-character vendor identification
mmmmmm = six characters specifying the sensor model
vvv = three characters specifying the sensor version (operating system)
xxx…xx = up to 13 optional characters used for a serial number or other specific sensor information that is not relevant for operation of the data logger
<CR><LF> = terminates the response