EV607797 said:No voice application of any kind requires anything over CAT3, in fact voice circuits will work on "CAT Nothing", as in unrated cabling. Even CAT3 is overkill, so you will be fine.
The one exception to this might be ISDN where CAT5 or above is specified, however I can attest that I have four ISDN phones working in my home on spare pairs of existing CAT Nothing cable. Much of this is simply manufacturer hooplah.