I put togeteher this example for fun:
Suppose that:
L1 is a VOIP main line for the residence
L2 is a VOIP business line
L3 is a POTS FAX line which has DSL service
L4 is the nakes DSL line
Now suppose you want the following connections:
Den L1, L2 with a 2-line phone
Kit L1 & L2 with a two line phone
Bed L1
Office L2 and a Fax (L3) machine
Den Fax (L3) line for a sattellite system
RJ31x on L3 for an alarm system
Most FAX machines and alarm systems won't work with VOIP unoless the baud rate is restricted.
You can arrange things such that when a 6C4P plug is plugged into the Dena and Kitchen, both L1 and L2 are available with the 2 line phone without any adapters.
When a 6P2C plug is used in the bedrrom plugged into the RJ45, it has access to Line #1
For the office, you would need the adapter from l-com. The RJ45 from the adapter goes into the wall and each phone goes into L2 and Fax 6 conductor ports respectively.
For the satellite system, the adapter would be used as well.
At the other end:
The DSL splitter would be in the NID with the naked line on line #4 and the POTS service transferred to L2.
L2 would need an RJ31x jack to interface with an alarm system. This jack is special because with the jack unplugged it routes the input tot the output. With a plug, plugged into the jack, line seizure can occur.
The VOIP boxes need a way to get the wires to the distribution bus. L2 and L3 are already wired. If it was me, I would dedicate a line directly to the DSL modem and not make it available everywhere in the house.
Now, I'm going to throw a wrench in the fan for a moment. Suppose I installed a PERS (Personal Emergency Response System) which is pendant based that calls 911 through an alarm system.
The monitoring system has to be located in a central place which happens to be the bedroom. If I want the system to have line seizure capabilities, I'd have to install a RJ31x Keystone jack in the bedroom, so this is where some wiring changes wouold have to occur.
You can then see where some systems might become inflexible.
Verizon FIOS requires an RG6 and Ethernet connection at each TV.
Now there are home automation systems that may require an IR repeater. So with Ethernet taken up, the phone line taken uo (Sat system), there isn't anything left to to IR repeating.
This is where a central wiring location AND low voltage flex conduit comes in hand to add any additional wires needed.
THE BUILDER IS CORRECT THAT ONLY RJ45 JACKS NEED TO BE INSTALLED FOR BOTH PHONE AND DATA.
The proper jacks are designed such that pins don't get bent when the wrong plug is inserted. That's the major difference.
It's new technology. Embrace it.
Here is an example of the flexible low voltage raceway called Resi-gard.
Conduits & Raceways - HomeTech Solutions
The color is orange. Flex conduit for high voltage is blue.
Watch out for home automation systems like lighting controllers that also may need CAT5E or CAT6.
If this was a new home, I would have also wired the switches with 12/3 or 14/3, so that a neutral is available at the switch location. A lot of automation products are requiring a neutral at the switch.