A POTS line is a two-way line (both DID and DOD) thus no need for the provider to ask you. No need to ask you if it's wink start, loop start, ground start - or starts at all - because it does't go to a PBX where you program that. It's all done by the phone company, just like a telephone line to your house.You'll just plug in a phone at your end.
If you want to have those questions asked to you - order a CO trunk. They should ask how many lines you want in the trunk group as well as all those other questions you wish they would. You should have a PBX/ACD to translate too in this case.
Order a DID trunk group (known as ADL LOCI) only if you don't want to make outgoing calls on this trunk.You'll have to buy a range of DID numbers as well.
Order a DOD trunk group (Direct outward Dialing) (known as ADL LOCO) only if you don't want to recieve calls on this trunk. You'll only be able to make outgoing calls.
Order a PRI if you want 23 voice channels (known as bearer channels) and 1 control channel (knows as the "d-channel")
This "d-channel" will carry your signal and framing. This would be an ISDN T1. Then you'll get asked other questions, "Will that be B8ZS and ESF?" - "Which channel do want the control on?" - Two or more T1s, "Which circuit will be index 0, 1, 2, etc.?" "Have you ordered the DIDs?" "How many digits do want deleted?" "Do you want any digits inserted?" "What do you want for a DNIS?" .. and then you should ask, "What are the circuit IDs?" also ask "How many digits do you want to see on an outgoing call?"
You can order a T1 (24 channels) that isn't PRI - it could use 'e&m' signal (known as robbed bit). (Skip a few of the questions in this case.)
The translations for each kind of T1 will be a little different (signal group or not signal group, trunk group form etc) and to be honest I only know how to translate each in the Avaya system.
You can order other services other than ADL LOCI/LOCO on your T1 - (meg8, wats, etc: - ask the provider)
You can order an BRI too, if you don't need so may lines.