Alright, I've been reading a lot of topics the past two or three days and nothing seems to have asked this.

I am writing a PC side server for my andriod device, this is for exchanging some information and general debugging. Eventually I will be connecting to a SPP device to control a microcontroller.

I have managed, using the following (Android to pc) to connect to rfcomm channel 11 and exchange data between my android device and my pc.

Method m = device.getClass().getMethod("createRfcommSocket", new Class[] { int.class }); tmp = (BluetoothSocket) m.invoke(device, Integer.valueOf(11));

I have attempted the createRfcommSocketToServiceRecord(UUID) method, with absolutely no luck.

For the PC side, I have been using the C Bluez stack for linux. I have the following code which registers the service and opens a server socket:

int main(int argc, char **argv)
{
    struct sockaddr_rc loc_addr = { 0 }, rem_addr = { 0 };
    char buf[1024] = { 0 };
    char str[1024] = { 0 };
    int s, client, bytes_read;
    sdp_session_t *session;
    socklen_t opt = sizeof(rem_addr);

    session = register_service();
    s = socket(AF_BLUETOOTH, SOCK_STREAM, BTPROTO_RFCOMM);
    loc_addr.rc_family = AF_BLUETOOTH;
    loc_addr.rc_bdaddr = *BDADDR_ANY;
    loc_addr.rc_channel = (uint8_t) 11;
    bind(s, (struct sockaddr *)&loc_addr, sizeof(loc_addr));
    listen(s, 1);
    client = accept(s, (struct sockaddr *)&rem_addr, &opt);
    ba2str( &rem_addr.rc_bdaddr, buf );
    fprintf(stderr, "accepted connection from %s\n", buf);
    memset(buf, 0, sizeof(buf));
    bytes_read = read(client, buf, sizeof(buf));
    if( bytes_read > 0 ) {
     printf("received [%s]\n", buf);
    }
    sprintf(str,"to Android.");
    printf("sent [%s]\n",str);
    write(client, str, sizeof(str));
    close(client);
    close(s);
    sdp_close( session );

    return 0;
}

    sdp_session_t *register_service()
{

    uint32_t svc_uuid_int[] = { 0x00000000,0x00000000,0x00000000,0x00000000 };
    uint8_t rfcomm_channel = 11;
    const char *service_name = "Remote Host";
    const char *service_dsc = "What the remote should be connecting to.";
    const char *service_prov = "Your mother";

    uuid_t root_uuid, l2cap_uuid, rfcomm_uuid, svc_uuid;
    sdp_list_t *l2cap_list = 0, 
               *rfcomm_list = 0,
               *root_list = 0,
               *proto_list = 0, 
               *access_proto_list = 0;
    sdp_data_t *channel = 0, *psm = 0;

    sdp_record_t *record = sdp_record_alloc();

    // set the general service ID
    sdp_uuid128_create( &svc_uuid, &svc_uuid_int );
    sdp_set_service_id( record, svc_uuid );

    // make the service record publicly browsable
    sdp_uuid16_create(&root_uuid, PUBLIC_BROWSE_GROUP);
    root_list = sdp_list_append(0, &root_uuid);
    sdp_set_browse_groups( record, root_list );

    // set l2cap information
    sdp_uuid16_create(&l2cap_uuid, L2CAP_UUID);
    l2cap_list = sdp_list_append( 0, &l2cap_uuid );
    proto_list = sdp_list_append( 0, l2cap_list );

    // set rfcomm information
    sdp_uuid16_create(&rfcomm_uuid, RFCOMM_UUID);
    channel = sdp_data_alloc(SDP_UINT8, &rfcomm_channel);
    rfcomm_list = sdp_list_append( 0, &rfcomm_uuid );
    sdp_list_append( rfcomm_list, channel );
    sdp_list_append( proto_list, rfcomm_list );

    // attach protocol information to service record
    access_proto_list = sdp_list_append( 0, proto_list );
    sdp_set_access_protos( record, access_proto_list );

    // set the name, provider, and description
    sdp_set_info_attr(record, service_name, service_prov, service_dsc);

    int err = 0;
    sdp_session_t *session = 0;

    // connect to the local SDP server, register the service record, and 
    // disconnect
    session = sdp_connect( BDADDR_ANY, BDADDR_LOCAL, SDP_RETRY_IF_BUSY );
    err = sdp_record_register(session, record, 0);

    // cleanup
    //sdp_data_free( channel );
    sdp_list_free( l2cap_list, 0 );
    sdp_list_free( rfcomm_list, 0 );
    sdp_list_free( root_list, 0 );
    sdp_list_free( access_proto_list, 0 );

    return session;
}

And another piece of code, in addition to 'sdptool browse local' which can verifty that the service record is running on the pc:

int main(int argc, char **argv)
{
    uuid_t svc_uuid;
    uint32_t svc_uuid_int[] = { 0x00000000,0x00000000,0x00000000,0x00000000 };
    int err;
    bdaddr_t target;
    sdp_list_t *response_list = NULL, *search_list, *attrid_list;
    sdp_session_t *session = 0;

    str2ba( "01:23:45:67:89:AB", &target );

    // connect to the SDP server running on the remote machine
    session = sdp_connect( BDADDR_ANY, BDADDR_LOCAL, SDP_RETRY_IF_BUSY );

    // specify the UUID of the application we're searching for
    sdp_uuid128_create( &svc_uuid, &svc_uuid_int );
    search_list = sdp_list_append( NULL, &svc_uuid );

    // specify that we want a list of all the matching applications' attributes
    uint32_t range = 0x0000ffff;
    attrid_list = sdp_list_append( NULL, &range );

    // get a list of service records that have UUID 0xabcd
    err = sdp_service_search_attr_req( session, search_list, \
            SDP_ATTR_REQ_RANGE, attrid_list, &response_list);

    sdp_list_t *r = response_list;

    // go through each of the service records
    for (; r; r = r->next ) {
        sdp_record_t *rec = (sdp_record_t*) r->data;
        sdp_list_t *proto_list;

        // get a list of the protocol sequences
        if( sdp_get_access_protos( rec, &proto_list ) == 0 ) {
        sdp_list_t *p = proto_list;

        // go through each protocol sequence
        for( ; p ; p = p->next ) {
            sdp_list_t *pds = (sdp_list_t*)p->data;

            // go through each protocol list of the protocol sequence
            for( ; pds ; pds = pds->next ) {

                // check the protocol attributes
                sdp_data_t *d = (sdp_data_t*)pds->data;
                int proto = 0;
                for( ; d; d = d->next ) {
                    switch( d->dtd ) { 
                        case SDP_UUID16:
                        case SDP_UUID32:
                        case SDP_UUID128:
                            proto = sdp_uuid_to_proto( &d->val.uuid );
                            break;
                        case SDP_UINT8:
                            if( proto == RFCOMM_UUID ) {
                                printf("rfcomm channel: %d\n",d->val.int8);
                            }
                            break;
                    }
                }
            }
            sdp_list_free( (sdp_list_t*)p->data, 0 );
        }
        sdp_list_free( proto_list, 0 );

        }

        printf("found service record 0x%x\n", rec->handle);
        sdp_record_free( rec );
    }

    sdp_close(session);
}

Output:
$ ./search 
rfcomm channel: 11
found service record 0x10008

sdptool:
Service Name: Remote Host
Service Description: What the remote should be connecting to.
Service Provider: Your mother
Service RecHandle: 0x10008
Protocol Descriptor List:
  "L2CAP" (0x0100)
  "RFCOMM" (0x0003)
    Channel: 11

And for logcat I'm getting this:

07-22 15:57:06.087: ERROR/BTLD(215): ****************search UUID = 0000***********
07-22 15:57:06.087: INFO//system/bin/btld(209):         btapp_dm_GetRemoteServiceChannel()
07-22 15:57:06.087: INFO//system/bin/btld(209): ##### USerial_Ioctl: BT_Wake, 0x8003 ####
07-22 15:57:06.097: INFO/ActivityManager(88): Displayed activity com.example.socktest/.socktest: 79 ms (total 79 ms)
07-22 15:57:06.697: INFO//system/bin/btld(209): ##### USerial_Ioctl: BT_Sleep, 0x8004 ####
07-22 15:57:07.517: WARN/BTLD(215): ccb timer ticks: 2147483648
07-22 15:57:07.517: INFO//system/bin/btld(209): ##### USerial_Ioctl: BT_Wake, 0x8003 ####
07-22 15:57:07.547: WARN/BTLD(215): info:x10
07-22 15:57:07.547: INFO/BTL-IFS(215): send_ctrl_msg: [BTL_IFS CTRL] send BTLIF_DTUN_SIGNAL_EVT (CTRL) 10 pbytes (hdl 14)
07-22 15:57:07.547: DEBUG/DTUN_HCID_BZ4(253):         dtun_dm_sig_link_up()
07-22 15:57:07.547: INFO/DTUN_HCID_BZ4(253): dtun_dm_sig_link_up: dummy_handle = 342
07-22 15:57:07.547: DEBUG/ADAPTER(253): adapter_get_device(00:02:72:AB:7C:EE)
07-22 15:57:07.547: ERROR/BluetoothEventLoop.cpp(88): pollData[0] is revented, check next one
07-22 15:57:07.547: ERROR/BluetoothEventLoop.cpp(88): event_filter: Received signal org.bluez.Device:PropertyChanged from /org/bluez/253/hci0/dev_00_02_72_AB_7C_EE
07-22 15:57:07.777: WARN/BTLD(215): process_service_search_attr_rsp
07-22 15:57:07.787: INFO/BTL-IFS(215): send_ctrl_msg: [BTL_IFS CTRL] send BTLIF_DTUN_SIGNAL_EVT (CTRL) 13 pbytes (hdl 14)
07-22 15:57:07.787: INFO/DTUN_HCID_BZ4(253): dtun_dm_sig_rmt_service_channel: success=0, service=00000000
07-22 15:57:07.787: ERROR/DTUN_HCID_BZ4(253): discovery unsuccessful!
07-22 15:57:08.497: INFO//system/bin/btld(209): ##### USerial_Ioctl: BT_Sleep, 0x8004 ####
07-22 15:57:09.507: INFO//system/bin/btld(209): ##### USerial_Ioctl: BT_Wake, 0x8003 ####
07-22 15:57:09.597: INFO/BTL-IFS(215): send_ctrl_msg: [BTL_IFS CTRL] send BTLIF_DTUN_SIGNAL_EVT (CTRL) 11 pbytes (hdl 14)
07-22 15:57:09.597: DEBUG/DTUN_HCID_BZ4(253):         dtun_dm_sig_link_down()
07-22 15:57:09.597: INFO/DTUN_HCID_BZ4(253): dtun_dm_sig_link_down device = 0xf7a0 handle = 342 reason = 22
07-22 15:57:09.597: ERROR/BluetoothEventLoop.cpp(88): pollData[0] is revented, check next one
07-22 15:57:09.597: ERROR/BluetoothEventLoop.cpp(88): event_filter: Received signal org.bluez.Device:PropertyChanged from /org/bluez/253/hci0/dev_00_02_72_AB_7C_EE
07-22 15:57:09.597: DEBUG/BluetoothA2dpService(88): Received intent Intent { act=android.bluetooth.device.action.ACL_DISCONNECTED (has extras) }
07-22 15:57:10.107: INFO//system/bin/btld(209): ##### USerial_Ioctl: BT_Sleep, 0x8004 ####
07-22 15:57:12.107: DEBUG/BluetoothService(88): Cleaning up failed UUID channel lookup: 00:02:72:AB:7C:EE 00000000-0000-0000-0000-000000000000
07-22 15:57:12.107: ERROR/Socket Test(5234): connect() failed
07-22 15:57:12.107: DEBUG/ASOCKWRP(5234): asocket_abort [31,32,33]
07-22 15:57:12.107: INFO/BLZ20_WRAPPER(5234): blz20_wrp_shutdown: s 31, how 2
07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): blz20_wrp_shutdown:  fd (-1:31), bta -1, rc 0, wflags 0x0
07-22 15:57:12.107: INFO/BLZ20_WRAPPER(5234): __close_prot_rfcomm: fd 31
07-22 15:57:12.107: INFO/BLZ20_WRAPPER(5234): __close_prot_rfcomm: bind not completed on this socket
07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): btlif_signal_event:  fd (-1:31), bta -1, rc 0, wflags 0x0
07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): btlif_signal_event: event BTLIF_BTS_EVT_ABORT matched
07-22 15:57:12.107: DEBUG/BTL_IFC_WRP(5234): wrp_close_s_only: wrp_close_s_only [31] (31:-1) []
07-22 15:57:12.107: DEBUG/BTL_IFC_WRP(5234): wrp_close_s_only: data socket closed
07-22 15:57:12.107: DEBUG/BTL_IFC_WRP(5234): wsactive_del: delete wsock 31 from active list [ad3e1494]
07-22 15:57:12.107: DEBUG/BTL_IFC_WRP(5234): wrp_close_s_only: wsock fully closed, return to pool
07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): btsk_free: success
07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): blz20_wrp_write: wrote 1 bytes out of 1 on fd 33
07-22 15:57:12.107: DEBUG/ASOCKWRP(5234): asocket_destroy
07-22 15:57:12.107: DEBUG/ASOCKWRP(5234): asocket_abort [31,32,33]
07-22 15:57:12.107: INFO/BLZ20_WRAPPER(5234): blz20_wrp_shutdown: s 31, how 2
07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): blz20_wrp_shutdown: btsk not found, normal close (31)
07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): blz20_wrp_write: wrote 1 bytes out of 1 on fd 33
07-22 15:57:12.107: INFO/BLZ20_WRAPPER(5234): blz20_wrp_close: s 33
07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): blz20_wrp_close: btsk not found, normal close (33)
07-22 15:57:12.107: INFO/BLZ20_WRAPPER(5234): blz20_wrp_close: s 32
07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): blz20_wrp_close: btsk not found, normal close (32)
07-22 15:57:12.107: INFO/BLZ20_WRAPPER(5234): blz20_wrp_close: s 31
07-22 15:57:12.107: DEBUG/BLZ20_WRAPPER(5234): blz20_wrp_close: btsk not found, normal close (31)
07-22 15:57:12.157: DEBUG/Sensors(88): close_akm, fd=151
07-22 15:57:12.167: ERROR/CachedBluetoothDevice(477): onUuidChanged: Time since last connect14970690
07-22 15:57:12.237: DEBUG/Socket Test(5234): -On Stop-

Sorry for bombarding you guys with what seems like a difficult question and a lot to read, but I've been working on this problem for a while and I've tried a lot of different things to get this working.

Let me reiterate, I can get it to work, but not using service discovery protocol. I've tried a several different UUIDs and on two different computers, although I only have my HTC Incredible to test with.

I've also heard some rumors that the BT stack wasn't working on the HTC Droid, but that isn't the case, at least, for PC interaction.