Faction Specific Units

[Mortar]

Ok, probably a question asked and answered somewhere but can't fine it so i'm asking...

Can someone point me to anyplace that describes what these units do? (i.e. Goliath, Sturmtiger, Radio Operator).

Most are obvious, but some like the Radio Operator confuse me. What does he do and how does he do it?

Is there a thread that describes all these faction specific units?

[Canidae]

If all else fails, a combination of either testing the units in an empty LAN or searching the net (ie. searching for 'black prince') should tell you about the units. If you tested the radio operator, for example, you could notice the huge amounts of artillery smoke grenades in his inventory and throw them in direct control to see the effect.