Bird Technologies 4421 - Manual (Page 45)

RS-232 Interface
33
Self Test (J0)
Function Initiates a hardware and software test.
Remarks Results are stored in the U1 status word (see “Status” on page 31).
“J0” must be sent each time before reading the result.
Writable Store (Wxxxxxx)
Function Storage for six bytes of ASCII data.
Remarks Data stored is lost when the 4421 is turned off.
Data is sent back as part of the U2 status word.