First, let me say that I am brand new to phone administration. I was just hired as a computer administrator (which I know a lot about) and the phone administration came with the job (which I know nothing about). Apparently no one here knows anything about the system either. They seem to barely be using any of the features... no voicemail, no welcome message, no directory, nothing. From what I can see, this is a Samsung Prostar DCS with 9 slots inside. They are labelled as follows:
PSU - PSU60
SLOT1 - TRK-A1
SLOT2 - TRK-C1
SLOT3 - TRK-C1
SLOT4 - DLI
SLOT5 - DLI
SLOT6 - 8SLI
SLOT7 - SLI
ROM - ROM1

Can you tell me the purpose of each of these pieces? Should I simply order a manual for this?

Also, I would like to know how to change the extensions of our keysets. We are using Samsung LCD 24B and LCD 12B keysets but the extensions are all over the place and not in order at all. Fortunately this is only a small company and these things can be fixed now without too much trouble.

Thanks for your time in helping out a noob.