At first view, when connected through the USB cable, it works as a memorystick (micro) reader pretty easily, when the file transfer mode is selected on the phone, and rrecognized as a USB mass storage device... however, I haven't tested any file transfer, and fear problems, as I read reports of weird FAT 12 problems on other K series phones (google helps)... will have to test that.

Also working, still with USB cable, the serial emulation through cdc_acm, which was automatically recognised by udev et al. on my Debian testing... and then Wammu works very well on /dev/ttyACM0 device. It's then possible to access contacts, which is the main thing I'd like to backup.

Feel free to comment, ask.

Update 2006/11/02 : I've added details on ppp connection with my Debian system through bluetooth , and also on how to connect it to the Nokia 770

Update 2006/11/12 : I've added details on how to exchange files through the USB cable and OBEX.

Links to other pages about this phone :

Bluetooth capabilities

Here are some of the interesting Bluetooth characteristics detected by the bluetooth tools on GNU/Linux :

$ hcitool scan
Scanning ...
        XX:XX:...:XX       K610i

and :

$ sdptool browse XX:XX:...:XX
Browsing XX:XX:...:XX ...
Service Description: Sony Ericsson K610
Service RecHandle: 0x10000
Service Class ID List:
  "PnP Information" (0x1200)

Service Name: OBEX SyncML Client
Service RecHandle: 0x10001
Service Class ID List:
  UUID 128: 00000002-0000-1000-8000-0002ee000002
Protocol Descriptor List:
  "L2CAP" (0x0100)
  "RFCOMM" (0x0003)
    Channel: 1
  "OBEX" (0x0008)

Service Name: Dial-up Networking
Service RecHandle: 0x10002
Service Class ID List:
  "Dialup Networking" (0x1103)
  "Generic Networking" (0x1201)
Protocol Descriptor List:
  "L2CAP" (0x0100)
  "RFCOMM" (0x0003)
    Channel: 2
Profile Descriptor List:
  "Dialup Networking" (0x1103)
    Version: 0x0100

Service Name: Serial Port
Service RecHandle: 0x10003
Service Class ID List:
  "Serial Port" (0x1101)
Protocol Descriptor List:
  "L2CAP" (0x0100)
  "RFCOMM" (0x0003)
    Channel: 3

Service Name: PAN Network Access Point
Service Description: NAP provides access to internet for one connecting PANu
Service RecHandle: 0x10008
Service Class ID List:
  "Network Access Point" (0x1116)
Protocol Descriptor List:
  "L2CAP" (0x0100)
    PSM: 15
  "BNEP" (0x000f)
    Version: 0x0100
    SEQ8: 0 6 dd
Language Base Attr List:
  code_ISO639: 0x656e
  encoding:    0x6a
  base_offset: 0x100
Profile Descriptor List:
  "Network Access Point" (0x1116)
    Version: 0x0100

Service Name: Hands-Free Gateway
Service RecHandle: 0x10009
Service Class ID List:
  "Handfree Audio Gateway" (0x111f)
  "Generic Audio" (0x1203)
Protocol Descriptor List:
  "L2CAP" (0x0100)
  "RFCOMM" (0x0003)
    Channel: 4
Profile Descriptor List:
  "Handsfree" (0x111e)
    Version: 0x0105

Service Name: Headset Gateway
Service RecHandle: 0x1000a
Service Class ID List:
  "Headset Audio Gateway" (0x1112)
  "Generic Audio" (0x1203)
Protocol Descriptor List:
  "L2CAP" (0x0100)
  "RFCOMM" (0x0003)
    Channel: 5
Profile Descriptor List:
  "Headset" (0x1108)
    Version: 0x0100

Service Name: OBEX Object Push
Service RecHandle: 0x1000b
Service Class ID List:
  "OBEX Object Push" (0x1105)
Protocol Descriptor List:
  "L2CAP" (0x0100)
  "RFCOMM" (0x0003)
    Channel: 6
  "OBEX" (0x0008)
Profile Descriptor List:
  "OBEX Object Push" (0x1105)
    Version: 0x0100

Service Name: OBEX File Transfer
Service RecHandle: 0x1000c
Service Class ID List:
  "OBEX File Transfer" (0x1106)
Protocol Descriptor List:
  "L2CAP" (0x0100)
  "RFCOMM" (0x0003)
    Channel: 7
  "OBEX" (0x0008)
Profile Descriptor List:
  "OBEX File Transfer" (0x1106)
    Version: 0x0100

Service Name: OBEX IrMC Sync Server
Service RecHandle: 0x1000d
Service Class ID List:
  "IrMC Sync" (0x1104)
Protocol Descriptor List:
  "L2CAP" (0x0100)
  "RFCOMM" (0x0003)
    Channel: 8
  "OBEX" (0x0008)
Profile Descriptor List:
  "IrMC Sync" (0x1104)
    Version: 0x0100

Service Name: HID Mouse & Keyboard
Service Description: Remote Control of PC applications and other devices
Service Provider: Sony Ericsson
Service RecHandle: 0x1000e
Service Class ID List:
  "Human Interface Device" (0x1124)
Protocol Descriptor List:
  "L2CAP" (0x0100)
    PSM: 17
  "HIDP" (0x0011)
Language Base Attr List:
  code_ISO639: 0x656e
  encoding:    0x6a
  base_offset: 0x100
Profile Descriptor List:
  "Human Interface Device" (0x1124)
    Version: 0x0100

Update 2006/11/12 : To get some details about the phone characteristics, it is also possible to issue :

$ obexftp -u 0 -U synch -S -g telecom/devinfo.txt
$ cat devinfo.txt
MANU:Sony Ericsson
MOD:K610i
SW-VERSION:prgCXC1250537_ORANGE_TH
SW-DATE:20R1CB001TTTT00
SN:3517xxxxxxxxx94
PB-TYPE-TX:VCARD2.1
PB-TYPE-RX:VCARD2.1
CAL-TYPE-TX:VCAL1.0
CAL-TYPE-RX:VCAL1.0
MSG-TYPE-TX:NONE
MSG-TYPE-RX:NONE
NOTE-TYPE-TX:VNOTE1.1
NOTE-TYPE-RX:VNOTE1.1
X-ERI-MELODY-TYPE-TX:EMELODY1.0
X-ERI-MELODY-TYPE-RX:EMELODY1.0
IRMC-VERSION:1.1
INBOX:MULTIPLE
MSG-SENT-BOX:NO