How To Connect An Android Phone To PC With Bluez

Question

I am developping an Android application that simply connect a phone with a computer.

I had connected two computer with this commands (from comand line/console): Server Listening with this:

sdptool add --channel=15 SP
rfcomm listen rfcomm4 15

Client connect to the server with this:

rfcomm connect rfcomm4 11:11:11:11:11:11 15

This is working ok. (I am using Linux with bluez) it generate a rfcomm4 device in /dev in each machine and i can send and recive thata like a serial port.

The problem comes when i want to do that from an android phone. First of all, in one computer i start the server like this:

sdptool add --channel=15 SP
rfcomm listen rfcomm4 15

Then, in the android app (made with eclipse and android sdk) in a new thread i do:

...
UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb");
...
BluetoothSocket tmp = remoteDevice.createInsecureRfcommSocketToServiceRecord(MY_UUID);
...
mBluetoothAdapter.cancelDiscovery();
...
mmSocket.connect();
...

But the conection never come up to the server... There are somes variables that i can not understand perfectly. That UUID... what is exaclty? I had read and read and it says that the channel goes in that long String... but... How? How can i put the channel 15 (the one i am listening in the server) in the uuid. other articles says that the uuid is something pre-stablished. and for the rfcomm it go that uuid...

I am not sure if i am doing the rigth aproach to have a simple comunication (like a chat) between a android phone and a linux PC with the bluez 2.25. (this version in the server CAN NOT BE CHANGED). If my aproach is wrong, i will apreciated that someone tell me how to do that.

Thank you very much!

@ashish thanks for reply!!

I do hcidump like you said in the computer, and when i UP the device with hciconfig hci0 up if give me this:

[root@FriendlyARM /]# hcidump -i hci0 -t
HCI sniffer - Bluetooth packet analyzer ver 2.5
device: hci0 snap_len: 1500 filter: 0xffffffff
2000-01-02 05:25:26.472669 < HCI Command: Read Local Supported Features (0x04|0x0003) plen 0
2000-01-02 05:25:26.474602 > HCI Event: Command Complete (0x0e) plen 12
    Read Local Supported Features (0x04|0x0003) ncmd 1
    status 0x00
    Features: 0xff 0xff 0x8d 0xfe 0x9b 0xf9 0x00 0x80
2000-01-02 05:25:26.474711 < HCI Command: Read Local Version Information (0x04|0x0001) plen 0
2000-01-02 05:25:26.476613 > HCI Event: Command Complete (0x0e) plen 12
    Read Local Version Information (0x04|0x0001) ncmd 1
    status 0x00
    HCI Version: 2.0 (0x3) HCI Revision: 0x3000
    LMP Version: 2.0 (0x3) LMP Subversion: 0x420b
    Manufacturer: Broadcom Corporation (15)
2000-01-02 05:25:26.479366 < HCI Command: Read Buffer Size (0x04|0x0005) plen 0
2000-01-02 05:25:26.481614 > HCI Event: Command Complete (0x0e) plen 11
    Read Buffer Size (0x04|0x0005) ncmd 1
    status 0x00
    ACL MTU 1017:8 SCO MTU 64:0
2000-01-02 05:25:26.481753 < HCI Command: Read BD ADDR (0x04|0x0009) plen 0
2000-01-02 05:25:26.483597 > HCI Event: Command Complete (0x0e) plen 10
    Read BD ADDR (0x04|0x0009) ncmd 1
    status 0x00 bdaddr 00:1B:10:00:2A:EC
2000-01-02 05:25:26.483719 < HCI Command: Read Class of Device (0x03|0x0023) plen 0
2000-01-02 05:25:26.485593 > HCI Event: Command Complete (0x0e) plen 7
    Read Class of Device (0x03|0x0023) ncmd 1
    status 0x00 class 0x000000
2000-01-02 05:25:26.485714 < HCI Command: Read Local Name (0x03|0x0014) plen 0
2000-01-02 05:25:26.503570 > HCI Event: Command Complete (0x0e) plen 252
    Read Local Name (0x03|0x0014) ncmd 1
    status 0x00 name 'BCM2045B'
2000-01-02 05:25:26.503671 < HCI Command: Read Voice Setting (0x03|0x0025) plen 0
2000-01-02 05:25:26.505593 > HCI Event: Command Complete (0x0e) plen 6
    Read Voice Setting (0x03|0x0025) ncmd 1
    status 0x00 voice setting 0x0060
2000-01-02 05:25:26.505715 < HCI Command: Set Event Filter (0x03|0x0005) plen 1
    type 0 condition 0
    Clear all filters
2000-01-02 05:25:26.507599 > HCI Event: Command Complete (0x0e) plen 4
    Set Event Filter (0x03|0x0005) ncmd 1
    status 0x00
2000-01-02 05:25:26.507711 < HCI Command: Write Page Timeout (0x03|0x0018) plen 2
    timeout 32768
2000-01-02 05:25:26.509594 > HCI Event: Command Complete (0x0e) plen 4
    Write Page Timeout (0x03|0x0018) ncmd 1
    status 0x00
2000-01-02 05:25:26.509700 < HCI Command: Write Connection Accept Timeout (0x03|0x0016) plen 2
    timeout 32000
2000-01-02 05:25:26.511604 > HCI Event: Command Complete (0x0e) plen 4
    Write Connection Accept Timeout (0x03|0x0016) ncmd 1
    status 0x00
2000-01-02 05:25:26.512423 < HCI Command: Write Scan Enable (0x03|0x001a) plen 1
    enable 3
2000-01-02 05:25:26.514583 > HCI Event: Command Complete (0x0e) plen 4
    Write Scan Enable (0x03|0x001a) ncmd 1
    status 0x00

Then... When i try the connection (from the android-phone TO the computer with the code that i put up, in the first post, with the generic RFCOMM UUID) the hcidump give me this:

2000-01-02 05:33:50.147694 > HCI Event: Connect Request (0x04) plen 10
    bdaddr CC:FE:3C:D3:83:7A class 0x5a020c type ACL
2000-01-02 05:33:50.147884 < HCI Command: Accept Connection Request (0x01|0x0009) plen 7
    bdaddr CC:FE:3C:D3:83:7A role 0x01
    Role: Slave
2000-01-02 05:33:50.150700 > HCI Event: Command Status (0x0f) plen 4
    Accept Connection Request (0x01|0x0009) status 0x00 ncmd 1
2000-01-02 05:33:50.305680 > HCI Event: Connect Complete (0x03) plen 11
    status 0x00 handle 11 bdaddr CC:FE:3C:D3:83:7A type ACL encrypt 0x00
2000-01-02 05:33:50.305816 < HCI Command: Read Remote Supported Features (0x01|0x001b) plen 2
    handle 11
2000-01-02 05:33:50.307692 > HCI Event: Command Status (0x0f) plen 4
    Read Remote Supported Features (0x01|0x001b) status 0x00 ncmd 1
2000-01-02 05:33:50.308689 > HCI Event: Read Remote Supported Features (0x0b) plen 11
    status 0x00 handle 11
    Features: 0xbf 0xfe 0xcf 0xfe 0xdb 0xff 0x7b 0x87
2000-01-02 05:33:50.308865 < HCI Command: Remote Name Request (0x01|0x0019) plen 10
    bdaddr CC:FE:3C:D3:83:7A mode 2 clkoffset 0x0000
2000-01-02 05:33:50.311689 > HCI Event: Command Status (0x0f) plen 4
    Remote Name Request (0x01|0x0019) status 0x00 ncmd 1
2000-01-02 05:33:50.331693 > HCI Event: Max Slots Change (0x1b) plen 3
    handle 11 slots 5
2000-01-02 05:33:50.346676 > ACL data: handle 11 flags 0x02 dlen 10
    L2CAP(s): Info req: type 2
2000-01-02 05:33:50.346801 < ACL data: handle 11 flags 0x02 dlen 16
    L2CAP(s): Info rsp: type 2 result 0
      Extended feature mask 0x00b8
        Enhanced Retransmission mode
        Streaming mode
        FCS Option
        Fixed Channels
2000-01-02 05:33:50.352689 > ACL data: handle 11 flags 0x02 dlen 10
    L2CAP(s): Info req: type 3
2000-01-02 05:33:50.352797 < ACL data: handle 11 flags 0x02 dlen 20
    L2CAP(s): Info rsp: type 3 result 0
      Fixed channel list 0x00000002
        L2CAP Signalling Channel
2000-01-02 05:33:50.356688 > ACL data: handle 11 flags 0x02 dlen 12
    L2CAP(s): Connect req: psm 1 scid 0x0045
2000-01-02 05:33:50.356797 < ACL data: handle 11 flags 0x02 dlen 16
    L2CAP(s): Connect rsp: dcid 0x0000 scid 0x0045 result 2 status 0
      Connection refused - PSM not supported
2000-01-02 05:33:50.366652 > HCI Event: Remote Name Req Complete (0x07) plen 255
    status 0x00 bdaddr CC:FE:3C:D3:83:7A name 'BigDaddy'
2000-01-02 05:33:50.596654 > HCI Event: Number of Completed Packets (0x13) plen 5
        handle 11 packets 3
2000-01-02 05:33:54.310068 < HCI Command: Disconnect (0x01|0x0006) plen 3
    handle 11 reason 0x13
    Reason: Remote User Terminated Connection
2000-01-02 05:33:54.312334 > HCI Event: Command Status (0x0f) plen 4
    Disconnect (0x01|0x0006) status 0x00 ncmd 1
2000-01-02 05:33:54.460326 > HCI Event: Disconn Complete (0x05) plen 4
    status 0x00 handle 11 reason 0x16
    Reason: Connection Terminated by Local Host

But the computer server keep with this:

[root@FriendlyARM /]# sdptool add --channel=15 SP
[root@FriendlyARM /]# rfcomm listen rfcomm4 15
Waiting for connection on channel 15

So the phone-device dows not connect with the computer... (obviosly) but... why? Do you have any idea what i am doing wrong?

My Goal is to get a rfcommX port in each device to change mensage... (Like a chat)

Check for UUID [here](http://stackoverflow.com/questions/13964342/android-how-do-bluetooth-uuids-work) — ashish, Jul 03 '13 at 04:17
@ashish Thanks for reply!! Yes... I had read It... and some links tell me how create a conection between TWO ANDROID DEVICES. But no one have an example on how to do it if one of the device is a Computer with bluez. I mean... with the comands sdptool and rfcomm like i post before we create a port in the computer and make it listening for a conection... How can i get the uuid of that machine->serviceRFComm that i had just created. ? (From Linux Command line) — Joaquin, Jul 03 '13 at 11:46
per my undestanding, you have created a Serial port profile in bluez(SP service name) which 128 bit UUID is correct in your android code, with hcidump are you able to get connection request in linux — ashish, Jul 03 '13 at 12:23
The UUID you are using is reserved for the serial port profile. It is possible that your linux box has a different port assigned to SPP, in which case it would make sense that you are not connecting over 15. The android phone will attempt to connect to whichever port is registered in the service discovery record for SPP for your computer (which may not be port 15). Also, you could try createRfcommSocketToServiceRecord so it is secure. — TwinPrimesAreEz, Apr 04 '14 at 16:37

How To Connect An Android Phone To PC With Bluez

0 Answers0