I hate to get involved in this discussion, since it seems to have digressed from the original question rather significantly. However, I keep seeing people say the original question referred to Category 3 or Category 5. I've read the original question five or six times now, and I am quite certain he doesn't say anything about what grade of cabling and 66 block termination he intends to use. All he says is that it is his first "telephone" cabling job, he has prior CAT5 experience, and the installer recommends using 6P6C USOC jacks and 66 blocks. I can see why we would assume he intends to use Category 3 because of the 6P6C USOC jack _recommendation_, but it is just an assumption as far as I can tell.
For Wally130:
Category 3 and Category 5 termination on 66 blocks has been addressed already in this thread. However, 6P6C USOC jacks and 66 Blocks are the "standard" telephone cable installation... if your building is older or your cable installer does not keep up with current standards. The minimum you should consider for a new installation is Category 5 8P8C jacks, Category 5 cable, and Category 5 66/110 blocks or patch panels. Category 5e cable and termination is recommended. 8P8C jacks will accept most telephone cables, and if you wire them with the 568A wiring scheme the first two pairs will be compatible with the USOC wiring scheme. This is much better than what is needed for basic telephone service, but it allows your wiring to handle current needs and future applications with minimum upgrading.
Check with your telephone system installer and see if he uses all three pairs or only the first two. If he only uses the first two, go with Category 5 or Category 5e parts and 568A wiring. If he uses all three pairs, ask him if he can install using the 8P8C jacks and 568A wiring. If he says no, then you may want to look at his experience and qualifications again. Any competent installer should be able to work within this system.
I hope this is helpful to you. If you have any questions about this, just ask.
Good Luck,
David Hall