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#69532 by davevt98
Mon Nov 22, 2010 9:55 am
murphy wrote:That is used to distribute 4 incoming telephone lines to 8 different locations (4 phone lines is 8 wires and an RJ-45 jack has 8 wires. It uses RJ-45 jacks. It also has the ability to feed the line capture capability of an alarm system. It's a dumb design because it uses the same connectors as a LAN cable.

If you plug an active phone line into an LAN port it will instantly destroy the LAN port. Phone lines have 48 volts on them when on hook and 96 volts when a ringing signal is present. LAN ports are not designed to handle that much voltage.

You do not want identical jacks on your wall that serve two radically different purposes.


How do I set this up then? I am getting more and more confused on how they wired this. Do newer phones use rj45 jacks instead?
#69552 by tommies
Mon Nov 22, 2010 7:22 pm
davevt98 wrote:
murphy wrote:That is used to distribute 4 incoming telephone lines to 8 different locations (4 phone lines is 8 wires and an RJ-45 jack has 8 wires. It uses RJ-45 jacks. It also has the ability to feed the line capture capability of an alarm system. It's a dumb design because it uses the same connectors as a LAN cable.

If you plug an active phone line into an LAN port it will instantly destroy the LAN port. Phone lines have 48 volts on them when on hook and 96 volts when a ringing signal is present. LAN ports are not designed to handle that much voltage.

You do not want identical jacks on your wall that serve two radically different purposes.


How do I set this up then? I am getting more and more confused on how they wired this. Do newer phones use rj45 jacks instead?

No, but any phone cord will fit just fine into an RJ-45 jack or a standard phone jack (RJ-11.)

The solution is very simple,
  • first you need to locate the wall jacks, (of which you want to use with ooma and your phones.) and label them as such.
  • go to your central panel and locate the cables that connects to those wall jack, and remove them from the internet switch.
  • plug those plugs into the telephone panel. Optional, you can feed the cable (which connect to the jack that connects to hte PHONE port of ooma) to the top jack to the left--I assume it the connector for line 1.
  • cover the 3 jacks to the left with some kind of tape to prevent accidental connect the telco line into them.
and you all set.

This way, your house wiring supports two phone lines with a standard RJ-45 jack.
#69591 by EricJRW
Tue Nov 23, 2010 2:11 pm
murphy wrote:That is used to distribute 4 incoming telephone lines to 8 different locations (4 phone lines is 8 wires and an RJ-45 jack has 8 wires. It uses RJ-45 jacks. It also has the ability to feed the line capture capability of an alarm system. It's a dumb design because it uses the same connectors as a LAN cable.

If you plug an active phone line into an LAN port it will instantly destroy the LAN port. Phone lines have 48 volts on them when on hook and 96 volts when a ringing signal is present. LAN ports are not designed to handle that much voltage.

You do not want identical jacks on your wall that serve two radically different purposes.


Not necessarily. Since an Ethernet connection is using pins 1,2, 3 & 6 and a single line telephone uses pins 4 & 5, as long as the "LAN port" is not electrically connected to the two pins in the center (4&5) you won't destroy the network device. This is why the pin-out for Ethernet is the way it is... So if someone plugs in a single-line phone line it won't fry the port.

Of course if you are running two phone lines on a single piece of CAT 5 (or 6) cable, then line 1 is 4&5 and line two is (typically) 3&6, then you could have problems!
#69602 by tommies
Tue Nov 23, 2010 4:45 pm
EricJRW wrote:
murphy wrote:That is used to distribute 4 incoming telephone lines to 8 different locations (4 phone lines is 8 wires and an RJ-45 jack has 8 wires. It uses RJ-45 jacks. It also has the ability to feed the line capture capability of an alarm system. It's a dumb design because it uses the same connectors as a LAN cable.

If you plug an active phone line into an LAN port it will instantly destroy the LAN port. Phone lines have 48 volts on them when on hook and 96 volts when a ringing signal is present. LAN ports are not designed to handle that much voltage.

You do not want identical jacks on your wall that serve two radically different purposes.


Not necessarily. Since an Ethernet connection is using pins 1,2, 3 & 6 and a single line telephone uses pins 4 & 5, as long as the "LAN port" is not electrically connected to the two pins in the center (4&5) you won't destroy the network device. This is why the pin-out for Ethernet is the way it is... So if someone plugs in a single-line phone line it won't fry the port.

Of course if you are running two phone lines on a single piece of CAT 5 (or 6) cable, then line 1 is 4&5 and line two is (typically) 3&6, then you could have problems!

The text highlighted in blue is only true in 100BASE-TX. However, 1000BASE-T (gigabit ethernet) uses all 4 pairs, and the OP does have a gigabit router. What Murphy said still hold true.
#69610 by EricJRW
Tue Nov 23, 2010 9:19 pm
tommies wrote:
EricJRW wrote:
murphy wrote:That is used to distribute 4 incoming telephone lines to 8 different locations (4 phone lines is 8 wires and an RJ-45 jack has 8 wires. It uses RJ-45 jacks. It also has the ability to feed the line capture capability of an alarm system. It's a dumb design because it uses the same connectors as a LAN cable.

If you plug an active phone line into an LAN port it will instantly destroy the LAN port. Phone lines have 48 volts on them when on hook and 96 volts when a ringing signal is present. LAN ports are not designed to handle that much voltage.

You do not want identical jacks on your wall that serve two radically different purposes.


Not necessarily. Since an Ethernet connection is using pins 1,2, 3 & 6 and a single line telephone uses pins 4 & 5, as long as the "LAN port" is not electrically connected to the two pins in the center (4&5) you won't destroy the network device. This is why the pin-out for Ethernet is the way it is... So if someone plugs in a single-line phone line it won't fry the port.

Of course if you are running two phone lines on a single piece of CAT 5 (or 6) cable, then line 1 is 4&5 and line two is (typically) 3&6, then you could have problems!

The text highlighted in blue is only true in 100BASE-TX. However, 1000BASE-T (gigabit ethernet) uses all 4 pairs, and the OP does have a gigabit router. What Murphy said still hold true.

Good point... I don't have experience with gigabit, so I'll need to squirrel that info away. Scary that the safety of sub gig pinouts is now a cause for concern.

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