Hello all,
  I am programming for transferring data between my Linux box and mobile phone. But while transferring large files it takes quiet a few time.
  I want to achieve maximum data transfer rates without affecting reliability of system. I am using "object push service" for this. And tried changing default MTU size in /usr/include/openobex/obex_const.h
  But got same results.
  Can anyone tell me how can i increase MTU size? Or is there any limitation on it? (I think Max. MTU size can be 64k).
  Any help or suggestions are appreciated.
(partial) hcidump looks something like this:-

    L2CAP(d): cid 0x0040 len 7 [psm 3]
      RFCOMM(d): UIH: cr 0 dlci 8 pf 0 ilen 3 fcs 0x80
< ACL data: handle 1 flags 0x02 dlen 678
< ACL data: handle 1 flags 0x01 dlen 338
    L2CAP(d): cid 0x0046 len 1012 [psm 3]
      RFCOMM(d): UIH: cr 1 dlci 8 pf 0 ilen 1007 fcs 0x5a
< ACL data: handle 1 flags 0x02 dlen 25
    L2CAP(d): cid 0x0046 len 21 [psm 3]
      RFCOMM(d): UIH: cr 1 dlci 8 pf 0 ilen 17 fcs 0x5a
> HCI Event: Number of Completed Packets (0x13) plen 5
> HCI Event: Number of Completed Packets (0x13) plen 5
> HCI Event: Number of Completed Packets (0x13) plen 5
> ACL data: handle 1 flags 0x02 dlen 11
    L2CAP(d): cid 0x0040 len 7 [psm 3]
      RFCOMM(d): UIH: cr 0 dlci 8 pf 0 ilen 3 fcs 0x80
< ACL data: handle 1 flags 0x02 dlen 678
< ACL data: handle 1 flags 0x01 dlen 338
    L2CAP(d): cid 0x0046 len 1012 [psm 3]
      RFCOMM(d): UIH: cr 1 dlci 8 pf 0 ilen 1007 fcs 0x5a
< ACL data: handle 1 flags 0x02 dlen 25
    L2CAP(d): cid 0x0046 len 21 [psm 3]
      RFCOMM(d): UIH: cr 1 dlci 8 pf 0 ilen 17 fcs 0x5a
> HCI Event: Number of Completed Packets (0x13) plen 5
> HCI Event: Number of Completed Packets (0x13) plen 5
> HCI Event: Number of Completed Packets (0x13) plen 5
> ACL data: handle 1 flags 0x02 dlen 11
    L2CAP(d): cid 0x0040 len 7 [psm 3]
      RFCOMM(d): UIH: cr 0 dlci 8 pf 0 ilen 3 fcs 0x80
< ACL data: handle 1 flags 0x02 dlen 678
< ACL data: handle 1 flags 0x01 dlen 338
    L2CAP(d): cid 0x0046 len 1012 [psm 3]
      RFCOMM(d): UIH: cr 1 dlci 8 pf 0 ilen 1007 fcs 0x5a
< ACL data: handle 1 flags 0x02 dlen 25
    L2CAP(d): cid 0x0046 len 21 [psm 3]
      RFCOMM(d): UIH: cr 1 dlci 8 pf 0 ilen 17 fcs 0x5a
> HCI Event: Number of Completed Packets (0x13) plen 5
> HCI Event: Number of Completed Packets (0x13) plen 5
> HCI Event: Number of Completed Packets (0x13) plen 5
> ACL data: handle 1 flags 0x02 dlen 11
    L2CAP(d): cid 0x0040 len 7 [psm 3]
      RFCOMM(d): UIH: cr 0 dlci 8 pf 0 ilen 3 fcs 0x80
< ACL data: handle 1 flags 0x02 dlen 678
< ACL data: handle 1 flags 0x01 dlen 338
    L2CAP(d): cid 0x0046 len 1012 [psm 3]
      RFCOMM(d): UIH: cr 1 dlci 8 pf 0 ilen 1007 fcs 0x5a
< ACL data: handle 1 flags 0x02 dlen 25
    L2CAP(d): cid 0x0046 len 21 [psm 3]
      RFCOMM(d): UIH: cr 1 dlci 8 pf 0 ilen 17 fcs 0x5a
> HCI Event: Number of Completed Packets (0x13) plen 5
> HCI Event: Number of Completed Packets (0x13) plen 5
> HCI Event: Number of Completed Packets (0x13) plen 5
> ACL data: handle 1 flags 0x02 dlen 11
    L2CAP(d): cid 0x0040 len 7 [psm 3]
      RFCOMM(d): UIH: cr 0 dlci 8 pf 0 ilen 3 fcs 0x80
< ACL data: handle 1 flags 0x02 dlen 678
< ACL data: handle 1 flags 0x01 dlen 338
    L2CAP(d): cid 0x0046 len 1012 [psm 3]
      RFCOMM(d): UIH: cr 1 dlci 8 pf 0 ilen 1007 fcs 0x5a
< ACL data: handle 1 flags 0x02 dlen 25
    L2CAP(d): cid 0x0046 len 21 [psm 3]
      RFCOMM(d): UIH: cr 1 dlci 8 pf 0 ilen 17 fcs 0x5a
> HCI Event: Number of Completed Packets (0x13) plen 5
> HCI Event: Number of Completed Packets (0x13) plen 5
> HCI Event: Number of Completed Packets (0x13) plen 5
> ACL data: handle 1 flags 0x02 dlen 11
    L2CAP(d): cid 0x0040 len 7 [psm 3]
      RFCOMM(d): UIH: cr 0 dlci 8 pf 0 ilen 3 fcs 0x80
< ACL data: handle 1 flags 0x02 dlen 678
< ACL data: handle 1 flags 0x01 dlen 338