User's Manual

60
www.lairdtech.com
Laird Technologies
BTM510/511
Bluetooth
®
Multimedia Module
 7. HFP(Hands-FreeProle)
The Hands-free prole (HFP) denes how two devices supporting HFP shall interact with each other on
a point-to-point basis. The use case for HFP is a hands-free unit that is connected wirelessly to an audio
gateway. The audio gateway is typically a cellular phone. The hands-free unit acts as audio input and
audio output of the cellular phone and allows to control typical telephony functions to be performed
without access to the actual phone.
A BTM5xx module is required to be controlled by a host processor using AT commands (hosted
operation mode). BTM5xx HFP implementation supports both Hands-free role and Audio gateway role.
An AT command beginning with AT+HF... indicates afliation to Hands-free role of HFP.
An AT command beginning with AT+HFG…indicates afliation to Audio Gateway role of HFP.
Version 1.5 of the hands-free prole is supported [5].
Table 3.28 below shows the feature requirements for this prole and the level of support on BTM5xx.
It is highly recommended to download the prole specication [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
HFP Feature Support in HF Support in AG
Specication BTM5xx Specication BTM5xx
1. Connection management M Yes M Yes
2. Phone status information M Yes M Yes
3. Audio Connection handling M Yes M Yes
4 Accept an incoming voice call M Yes M Yes
5. Reject an incoming voice call M Yes O Yes
6. Terminate a call M Yes M Yes
7. Audio Connection transfer during an ongoing call M Yes M Yes
8. Place a call with a phone number supplied by the HF O Yes M Yes
9. Place a call using memory dialing O Yes M Yes
10. Place a call to the last number dialed O Yes M Yes
11. Call waiting notication O Yes M Yes
12. Three way calling O (2) O (2)
13. Calling Line Identication (CLI) O Yes M Yes
14. Echo cancellation (EC) and noise reduction (NR) O (5) O (5)
15. Voice recognition activation O (5) O (5)
16. Attach a Phone number to a voice tag O (5) O (5)
17. Ability to transmit DTMF codes O (5) M (4)
18. Remote audio volume control O (1) O (1)
19. Respond and Hold O (2) O (2)
20. Subscriber Number Information O Yes M Yes
21a. Enhanced Call Status O (2) M Yes
21b. Enhanced Call Controls O (2) O (2)
M: mandatory
O: optional
(1) support planned for future AT rmware release
(2) support planned for future AT rmware release, but with low priority
(3) not planned to be supported for future AT rmware
(4) service level signalization only
(5) support for service level signalization only planned for future AT rmware release
Table 3.28: Hands-free Prole supported features on BTM5xx
AT COMMAND SET
REFERENCE