Hi,
As far as I know, Teltonika doesn't give out data sheets for their accessories. Do you just need a connector or the whole power supply?
The standard power supply for RUT955 is:
INPUT: 100-240 V, 50/60 Hz, 0.4 A Max
OUTPUT: 9.0 V, 1.0 A
The connector itself is a 2 pin industrial socket with a 3.5 mm pin pitch. Looks like this:
In general, the router's input voltage can be in the range of 9-30 VDC, so you don't necessarily need a PSU that is identical to standard one.
You'll find some more info on the subject here.