[Asterisk-Users] How many FXS/FXO ports do I need?

[Aaron O'Hara]

All,

I'm new to phone systems and phone wiring and I couldn't find an answer
to this question on the wiki or google.

My understanding is that a standard residential/business phone line
carries the signal over 2 wires.  Your 4-wire RJ11 wiring supports 2
phone lines.  Given that each line takes 2 wires, and there are 8 wires
in an FXO port, can I conceivably support 4 phone lines on one FXO port?

On the phone/FXS side of things, can you also have multiple lines per
FXS port?

If I want to hookup 5 phones to my residential phone service with 2
lines, what # of FXO & FXS ports do I need?

Thanks for your clarification...

-- Aaron