Commercial/Shore Power Connection

[Crabber82]

Good morning,
Proud new owner of a Vintage 1988 Wide Body. Totally new to the RV scene so my question is very basic. At the power connection station (driver side rear of bus behind wheels) there are three potential ports. There are two cords that came with the coach. One 50 amp 4 pronged plug and one 3 pronged 30 amp plug.

I am waiting on electrician to install a 240V 50 amp circuit to resolve the overall issue. But in the mean time I have a 120V 15 amp circuit (garage radio) available and a 240V 20 amp circuit available (my air compressor plug).

Does the 30 amp port and associated cord on my Wanderlodge use 120v or 240v? Does it matter? Or does it simply accept the power and then by some unknown and lesser understood (by me) magic make it work. I do understand that I can not run the major appliances at the lower "amps". All I am trying to do is power the lighting and charge the batteries while I begin some interior restoration.
I would rather use the 240v 20 amp circuit but clearly I don't want to mess up anything by utilizing he wrong voltage.

I have read the owners manual cover to cover and scoured this blog and can not find any mention or reference to this subject.

So the simple question is...Do the shore/commercial power ports and associated cords on my 1988 Wanderlodge need 240 source? 120 source? Or does it matter.