I was told by the installer that if there is a power outage that I still could use the phone for up to 8 hours under battery power.
Does this mean that it is a "regular" phone line that goes through optical cables, or is it a VOIP line?
Yes. "it is a "regular" phone line that goes through optical cables"
The ONT (Optical Network Terminal) requires utility power to convert your telephone's electrical signals to optical signals compatible with the fiber optic cable.
The ONT includes a battery back-up to provide temporary power in the event of a utility power failure.
VOIP is a different technique that essentially gives your telephone the very specialized functional appearance of a PC and competes solely on the internet with other PCs to get to the PSTN (Public Switched Telephone Network).
Verizon's FiOS telephone service still functions as a regular telephone with its own, dedicated, optical cable connection to the PSTN instead of the previously dedicated copper cable connection to the PSTN --aka Central Office.
Next question on this subject. Since I have Verizon FiOS TV and Internet service and have 2 regular phone lines, would it be cheaper/better to convert these to VOIP lines? Does Verizon offer this. What are the Pro's and Con's of this?
It would probably be cheaper to go VOIP with something like Vonage 'Zero'. Basic residential line service is a tariffed service, so how Verizon provides it, has nothing to do with the cost. If it is tariffed at X dollars per month, that is the price of basic service, no matter how Verizon elects to provide it.
I.E.whether it is over FIOS or Copper doesn't alter the price. FIOS actually carves up the optical spectrum, into several parts in the fiber, and the ONT. There is a section used for telephone, another for Internet, and still another for Television. With VOIP, you are dealing with an internet connection, and in generaly packets arriving out of sequence or lost are a nuisance that are sorted out by the TCP/IP protocol. The standard telephone service over VIOS is a seperate spectrum, and is handled like regular telephone traffic. It is not subject to the vagaries of TCP/IP, so call reliability tends to be a little higher, and the bandwidth to support the call is guaranteed to be available on the network. This is not the case with VOIP. Fortunately the network capacity has been growing so fast, that this is rarely an issue with VOIP.
so FIOS phone service is probably more reliable than VOIP. VOIP uses bandwidth from the Internet connection, FIOS telephone has its own dedicated bandwidth.
on the optical fiber, so does not have to compete with internet traffic.
I will point out that many of Verizon's systems use you telephone number as 'central locator', so if you don't have one provided by Verizon, support can get very frustrating, because they cannot find you! I already have this problem because my phone is still verizon copper, but TV and Internet are FIOS, and it just about took an act of G-D to get the FIOS services cross referenced to the copper pair.