Q.:	What is OBEX ?
A.:	OBEX is like HTTP with commands and header fields as single bytes. Resources are requested via a GET command and appropriate headers. In Bluetooth, IrDA, and (if the data cable is not simply an USB to serial converter based on USB CDC but on) USB CDC WMC (chapter 6.5), you should use the deticated sevices and APIs for OBEX. If your device does not offer those, use the AT command layer and its OBEX starting commands via Bluetooth Dial-up Networking, IrDA IrCOMM, or USB CDC ACM. Some devices do not support that either. In 3GPP TS 27.007 OBEX is started via AT+CPROT=0. Ericsson used AT*EOBEX and Sharp uses it beside the custom target PCSOFTWARE. Motorola uses AT+MODE=22 and Siemens used AT^SQWE=3. If possible use the correct Bluetooth, IrDA, and USB APIs for OBEX communication. Many other services use OBEX:  – Folder Browsing (File Transfer Profile; FTP) – IrMC … – MAP (Message Access Profile) … – PBAP (Phonebook Access Profile) … – SyncML …
Q.:	What is Folder Browsing ?
A.:	Folder Browsing allows to browse the storage of a device which looks like FTP to the user. The protocol uses OBEX and XML documents to load the description of a folder content and file attributes. Folder Browsing relies on the SetPath command of OBEX which must be issued to set the current folder before the folder content is loaded. Due to device bugs you should not use the GetParent attribute of SetPath and you should not include file separators in a Name attribute. If you go up one folder level, start at the root and go down each level with a separate SetPath. May be akward but the only solution for some Siemens mobile phones. 何思聰 provided an overview …