User's Manual

Class 1 Bluetooth v2.0 Module
User’s Guide
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6.4.9 RX<string>
This response is sent to the host when the unit is in online-command mode and S Register 531 is set to 3
and data arrives from a peer.
If the data from the string contains non-visual characters (for example ASCII 0 to 31 and ASCII 128 to
255), then those characters are translated into a three character escape sequence starting with ‘\’. For
example the embedded <cr><lf> sequence would be sent as the six character string \0D\0A.
If the data contains the character ‘"’ then it is sent as \22.
If the data contains the character ‘\’ then it is sent as \5C
6.4.10 AG<string>
This response is sent to the host when a serviced audio gateway connection is in progress and the profile
requires some action from the host.
6.5 Incoming Connections
The Laird device can be configured using the AT+BTP or AT+BTG command so that it scans for incoming
connections from other Bluetooth devices. It can also be configured via S Register 512 to be in this mode
by default on power up.
When the lower layers detect an incoming call, a RING 123456789012 string is sent to the host every
second. The command ATA is used to accept the connection and ATH to reject it.
On connection, if the S0 Register is >=0 then confirmation to the host is in the form:
CONNECT 123456789012
CONNECT 123456789012 A
CONNECT 123456789012 E
CONNECT 123456789012 AE
(A = Authenticated connection; E = Encryption enabled)
When S0 register is -1, neither RING nor CONNECT is sent to the host and the connection is silently
accepted.
If the S 100 register is non-zero, then after the ring indications specified by this register have been sent to
the host, and the host has failed to accept or reject the incoming connection, then an automatic ‘hangup’
is initiated.
6.6 Dropping Connections
In a conventional telephony modem, a call is normally terminated by first sending a +++ character
sequence enveloped by an escape sequence guard time (of the order of 100 to 1000 milliseconds) to
enter local command and connected mode and then the ATH command.
Laird Bluetooth modules provide a variety of ways of dropping a connection. One method is similar to the
above, but instead a ^^^ character sequence is used; this eliminates ambiguity when a data call is in
progress via a mobile phone which was established using the mobile phone’s Bluetooth AT modem. The
second method involves the host dropping the DTR (DSR from the module’s viewpoint) handshaking line.
Being able to drop a connection using the escape sequence ^^^ has a severe penalty on data throughput.
In fact, the data rate is of the order of 85 kbps instead of about 200 kbps. To cater for this performance hit,
the device’s connection drop capability is configurable to be in one of two modes.