All Dell Axim X5 Series PDA's have the same pinouts as follows:

01 GND (shield) ,
02 (No Connection)
03 +5.5V , also on USB charger cable PCB (red)
04 +5.5V , also on USB charger cable PCB (red)
05 +5.5V , also on USB charger cable PCB (red)
06 +5.5V , also on USB charger cable PCB (red)
07 +5.5V , also on USB charger cable PCB (red)
08 +5.5V , also on USB charger cable PCB (red)
09 (No Connection)
10 Unknown
11 (No Connection)
12 Unknown
13 Unknown
14 Unknown
15 GND (shield) ,
16 (No Connection)
17 (No Connection)
18 (No Connection)
19 (No Connection)
20 GND (shield) ,
21 GND (shield) ,
22 Unknown
23 Unknown
24 GND (shield) ,
25 USB Device, Data + (green) ,
26 USB Device, Data - (white) ,
27 GND (shield) ,
28 Unknown
29 Unknown
30 GND (shield) ,
31 TxD (grey) ,
32 RTS (red) ,
33 DTR (brown) ,
34 DSR (blue) ,
35 DCD (yellow) ,
36 RxD (green) ,
37 CTS (orange) ,
38 GND (shield) ,
39 GND (shield) ,
40 Unknown