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Questions tagged [l2cap]

Bluetooth Logical link control and adaptation protocol resides in the data link layer.

L2CAP is used within the Bluetooth protocol stack. It passes packets to either the Host Controller Interface (HCI) or on a hostless system, directly to the Link Manager/ACL link. L2CAP provides connection-oriented and connectionless data services to upper layer protocols with protocol multiplexing capability, segmentation and reassembly operation, and group abstractions. L2CAP permits higher level protocols and applications to transmit and receive L2CAP data packets up to 64 kilobytes in length.

L2CAP's functions include:

  • Multiplexing data between different higher layer protocols.
  • Segmentation and reassembly of packets.
  • Providing one-way transmission management of multicast data to a group of other Bluetooth devices.
  • Quality of service (QoS) management for higher layer protocols.
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How can I establish an AVRCP connection from Windows 7 (controller) to phone (target) using L2CAP on Widcomm SDK?

I am using the CL2Cap class in the Widcomm SDK on Win7. I am able to successfully establish the L2CAP connection and send the UNIT INFO command but the data returned is incorrect. I suspect that the stack has already established a connection and the…
gCoder
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Does the iPhone sdk support l2cap bluetooth sockets?

Does the iPhone sdk support l2cap bluetooth sockets? Any additional information about SDK classes, etc would be greatly appreciated.
zooropa
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How to open a L2CAP channel in a windows 10 GATT service?

We are trying to connect an iOS device to our BLE application in Windows 10 to send larger amounts of data. We were already able to successfully write data. To increase the throughput we want to implement L2CAP channel between both devices. While on…
Alexander Belokon
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View call stack of built-in Android app via Eclipse?

I am trying view the call stack of the Android bluetooth settings/setup app. Android 3.0 is able to pair with a bluetooth keyboard however the SDK does not expose this functionality. From what I understand, the keyboard uses the HID profile which…
Buurin
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How to send and receive data via CBL2CAPChannel

I'm trying to open an L2CAP channel between 2 iOS devices and transfer data both ways. One of the devices acts as a central the other one as a peripheral. On the peripheral side: I publish an L2CAPChannel like this: func…
Mr Stanev
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Proper way to setup NSStreams?

I'm writing a little peer-to-peer bluetooth chat app. What I'm currently doing is: let thread = Thread(block: { [weak self] in guard let `self` = self else { return } self.channel.inputStream.delegate = self …
Peter Prokop
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Multiple L2CAP channels on iOS (rdar://46227689)

I'm trying to open two L2CAP channels between iPhone and app running on MacOS. MacOS app published two channels: PSM=193 and PSM=194. I open those channels on iOS…
msmialko
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L2CAP Channel data transfer

I am working on developing BLE app using connection oriented channel . I am using nordic semiconductor nrf52 as a peripheral device and iPhone 6 as central manager. I have used predefined PSM value provided by Bluetooth SIG that is 0x0025. I am ble…
blueWings
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BlueZ: Using LE Data Packet Length Extension from the command line

One of the main features of Bluetooth 4.2 was LE Data Length Packet Length Extension, which allowed Bluetooth devices to increase the LE packet from 27 octets to 251 octets, therefore significantly improving throughput and battery life. Is there a…
Youssif Saeed
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Connecting with Bluetooth L2Cap to HID Device

Are there any workarounds to connect to HID device using L2CAP in JAVA ME (using JSR-82 specification implementation native to mobile device not BlueCove etc.)? I know that HID devices usually uses PSMs (Protocol Service Multiplexor) with 0x0011…
user1610090
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Cancelling retransmissions on a L2CAP socket

I was wondering if anyone can assist me with a problem that I have with C Bluetooth programming (Linux Bluez). I am using Ubuntu 10.04, BlueZ 4.60. My goal is to have a L2CAP socket in which there will be minimal delay for sending data between 2…
eranre
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Packet "0x71" transmitted by iPad over control channel in HIDP Bluetooth connection

iPad is transmitting a 0x71 packet immediately after connecting over the control L2CAP channel in a Bluetooth HIDP connection. Unless I respond with 0x00 byte immediately, over the same channel, iPad disconnects. What does 0x71 mean? I cannot find…
Ivan Vučica
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BluetoothSocket.connect() Android 12 Permission issue on certain devices

We use Bluetooth Low Energy L2CAP Channels (introduced in Android API Level 29) to transfer data to our BLE devices. Recently we've got reports that it's not working on this devices: Oppo Find X2 Pro, API Level 31 (Android 12) Sony Xperia 1 III,…
Niklas Dada
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can't send data through l2cap raw socket for local controller - [Errno 107] Transport endpoint is not connected

I tried to connect to my local bluetooth controller through l2cap layer in order to see which services I am supporting by using SDP protocol. **don't want to use sdptool with socket.socket(socket.AF_BLUETOOTH, socket.SOCK_RAW, socket.BTPROTO_L2CAP)…
avi_tzanani
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Android 10 L2CAP connection IOException timeout Wii Balance Board

Background A long time ago I was tasked with making a android app for the Wii Balance Board, after some screwing around I found that android no longer supported L2CAP. More research lead to understand that it was being re-added in Android 10. With…
Jameson
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