Есть у меня интересный документ "Compaq iPAQ H3600 Hardware Design Specification - Version 0.2f" (~250K

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Cradle connector

The iPAQ H3600 uses the cradle connector as a way to connect to the external world. The cradle connector supports RS-232C, USB and AC adapter power input. The pin assignment is in following table. The first 12 pins are physical signal pins, and the rest of the pins are frame ground.

Name Description Pin
1 V_ADP AC adapter power in
2 V_ADP AC adapter power in
3 DTR RS-232 Data Terminal Ready
4 GND Power ground
5 CTS RS-232 Clear To Send
6 RTS RS-232 Request To Send
7 TXD RS-232 Transmit Data (from the SA-1110)
8 RXD RS-232 Receive Data (from the SA-1110)
9 DCD RS-232 Data Carry Detect
10 GND Power ground
11 UDC_P USB positive data signal
12 USB_N USB negative data signal
13 FG Frame ground
14 FG Frame ground
15 FG Frame ground