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Laird Technologies
BTM510/511
Bluetooth
®
Multimedia Module
7.2 Audio Gateway Role (AG-HFP / HFG)
Audio gateway role is activated by setting flag 0x40 in S102 plus “AT&W” plus “atz“. Please refer
to Figure 3.23 (page 56) for a block diagram of an audio gateway with a BTM5xx in hosted
operation mode.
Table 3.28 shows the feature requirements for this profile and the level of support on BTM5xx. It is
highly recommended to download the profile specification [5] in order to understand the
procedures related to a certain AT command. For quick navigation, references to [5] are given in
this section which follow the syntax:
#<Feature>_<Section>
With:
<Feature> = HFP feature no. in Table 3.28 and Table 3.1 of [5]
<Section> = Appropriate Section in [5]
Example: #3_4.12
feature no. = 3, section = 4.12
7.2.1 Initiate Service Level Connection (SLC) from AG (#1_4.2)
AT+HFGD<bd_addr
hex
>
Initiate service level connection (SLC) from local audio gateway instance to remote device
with <bd_addr
hex
>. The remote device must support the Hands-free role (HF) of the
Hands-free profile (HFP).
Response:
SLC established: <cr,lf>CONNECT 123456789012,111E,><cr,lf>
Failed:
<cr,lf>NO CARRIER<cr,lf>
Or: <cr,lf>ERROR 59<cr,lf>
Or: <cr,lf>ERROR 63<cr,lf>
After an SLC connection has been established, the module remains in AT command mode.
S Register 531 is ignored for HFP connections.
7.2.2 Initiate Audio Connection from AG (#3_4.11)
AT+HFGA
Initiate audio connection from local audio gateway instance. An existing service level
connection is required.
Response:
Audio on:
<cr,lf>HFG”AU1”<cr,lf>
7.2.3 Release Audio Connection from AG (#3_4.12)
AT+HFGR
Release audio connection only. The service level connection will be retained.
Response:
Audio on:
<cr,lf>HFG”AU0”<cr,lf>
7.2.4 Release Entire Connection from AG (#1_4.3)
AT+HFGH
Release connection from local audio gateway instance. An ongoing call will be terminated
and a audio connection will be released if existing, SLC will be released anyway.
Response:
On audio disconnection: <cr,lf>HFG”AU0”<cr,lf>
(only if audio connected)
On SLC disconnection:
<cr,lf>NO CARRIER 111F<cr,lf>
Please also refer to Section 6, page 85.
AT COMMAND SET
REFERENCE