In WM 5.0 2 new LSPs are present by default, the dtpt_lsp and the autobind_lsp. This article will discuss the dtpt_lsp and the next article will talk about the autobind_lsp.

Desktop Passthrough (DTPT)  is the  technology that allows the CE device to talk on the desktop network while Active Sync is running.

DTPT is implemented using a socket level proxy technology.  A transport proxy client runs on CE, while a proxy server runs on the desktop as part of active sync.  DTPT_LSP is that transpart proxy client. 

DTPT_LSP effects the following winsock calls:

def WSPConnect (addr) :
    if is_dtpt_enabled():
        connect_to_dtpt_server()
        dtpt_server_connect_to(addr)
    else:
        let_connect_call_passthrough_to(addr)

[Author: Igor Dvorkin]