Honeywell HPB User Manual page 13

HPB/HPA User Manual
(1) A carriage return, <cr>, should follow each input. If the HPB has an established address of 12, for instance, then begin the command
with *12..instead of *00...
(2) The responses shown here begin with ?01.. and are for a null address HPB. That is, an HPB that has not yet established unit identification
(see ID command). If the HPB has an assigned address of 23, for instance, the response will begin with #23.. instead of ?01...
12
Note: See Section 5.10 for complete command descriptions.
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