Home Only, Automatic A, Automatic B are ways to connect to the networ
during the day when all wireless phones just did Cellular only (n
PCS).
Automatic A push to the phone to the Cellular A block
Automatic B push to the phone to the Cellular B block
Home Only would keep your phone on your home network or System ID (SID
today.
The today these fuctions will only kick in if you are having signa
problems or if select Home Only sometimes if your are not on your Hom
network like in Chiacgo and serviced in Atlanta the phone won't work
even if you are on your carriers network since the SID is different i
those areas.
System scan is more modern it checks the PRL for a perfered network an
try to home in on that.
Due to firmware on phones today it can overide these old features an
start homeing in on a certain network, even though you are tring t
push it to a different network.

Here is a list of 'SIDs' (http://tinyurl.com/3o7lw) if you need to fin
one.

Here is Verizon Cellular A Cellular B network 'map.
(http://tinyurl.com/5gjey) If Verizon has a wireless network no
covered on the map like most of Florida, Texas and other areas then i
is a PCS network Verizon is operating.

Hope this helps you ou