User's Manual Part 4

Appendix B — Bluetooth Configuration Commands and Specifications
6822 Series 80-Column Printer User’s Manual 135
• Commands that fail return the four character sequence NAK<CR>
• Commands that are accepted return the four character sequence
ACK<CR>
• Commands that return payload data use the format:
<command character><command type><command payload><CR>
<command character> is one character from the set: [a-z]
<command type> is one character for the set: [0-9]
<command payload> is variable in length.
<CR> is the command terminator.
The command character is the lower case version of the local host
command.
Operating Modes
The module interface has two modes:
• Bluetooth Link Active State
In this case the Serial Interface looks like a raw serial port (TxD,
RxD, CTS, etc. and GND). There is no intelligence in the Bluetooth
module from the serial interface perspective. This mode does not
support the command and control modes described below.
• Bluetooth Link Inactive State
This mode exists when a Bluetooth link does not exist. In this case,
the serial interface looks like a serial port that supports a number of
command and control modes.
On reset, the unit comes up in Bluetooth Link Inactive state. After the
first Bluetooth connection, the unit goes into Bluetooth Link Active
state. It stays in this state until the link is lost because the Master shuts it
down or there is an out-of-range condition, it then returns to the
Bluetooth Link Inactive state.