User's Manual

61
www.lairdtech.com
Laird Technologies
BTM510/511
Bluetooth
®
Multimedia Module
7.1 Hands-Free Unit Role (HF)
Hands-free role is activated by setting ag 0x10 in S102 plus “AT&W” plus “atz“. Figure 3.24
outlines a block diagram with a BTM5xx in hosted operation mode.
Figure 3.24 Hands-free unit block diagram
7.1.1 Initiate Service Level Connection (SLC) from HF (#1_4.2)
AT+HFD<bd_addr
hex
>
Initiate service level connection (SLC) from local hands-free instance to remote device
with <bd_addr
hex
>. The remote device must support the audio gateway role (AG) of
the Hands-free prole (HFP).
Response:
SLC established: <cr,lf>CONNECT 123456789012,111F,><cr,lf>
Failed: <cr,lf>NO CARRIER<cr,lf>
Or: <cr,lf>ERROR 59<cr,lf>
Or: <cr,lf>ERROR 63<cr,lf>
After a SLC connection has been established, the module remains in AT command mode.
S Register 531 is ignored for HFP connections.
7.1.2 Initiate Audio Connection from HF (#3_4.11)
AT+HFA
Initiate audio connection from local Hands-free instance. An existing service level
connection is required.
Response:
Audio on: <cr,lf>HF”AU1”<cr,lf>
7.1.3 Release Audio Connection from HF (#3_4.12)
AT+HFR
Release audio connection only. The service level connection will be retained.
Response:
Audio on: <cr,lf>HF”AU0”<cr,lf>
7.1.4 Release Entire Connection from HF (#1_4.3)
AT+HFH
Release connection from local Hands-free instance. Audio connection will be released if
existing, SLC will be released anyway.
Response:
On audio disconnection: <cr,lf>HF”AU0”<cr,lf> (only if audio connection exists)
On SLC disconnection: <cr,lf>NO CARRIER 111E<cr,lf>
Telephone control
(e.g set of buttons /
keypad / display)
Host
Controller
Speaker
Microphone
Echo
Cancellation
BTM5xx [HF]
Audio
AT command
interface
AT COMMAND SET
REFERENCE