I am trying to connect ( 1 line ) 2 phone wires ( they are blue and white ) from the wall to telephone socket, but i am not sure where the wires go and how can i identify them and where to connect them. And also can i split the wires and connect them on each cat3 socket?

socket front socket back

  • i guess that the manufacturer wasted money on color coding connections
    – jsotola
    Commented Nov 14, 2020 at 19:31
  • 1
    @jsotola: Yes but look at all the money he saved by omitting any and all usable information. Commented Nov 14, 2020 at 20:13
  • @Breveleri i would love to give you more information, but that is all i got. I live in a building i dont know where the wires go from here or anything else
    – MePo
    Commented Nov 15, 2020 at 15:23
  • What country is this? That jack doesn't follow any US standard for number / color code. Commented Nov 16, 2020 at 11:56
  • @batsplaterson. Im from Croatia, i googled before asking here ad figured out that this is not in any standard. Whoever did this took random wires he/she had
    – MePo
    Commented Nov 16, 2020 at 17:17

2 Answers 2


For a single line tip (red) should be 2, ring (green) should be 3. Blue is not really standard color for phone wiring except when part of 4pr, then blue tip(2), and blue/white ring (3). For verification of your building you would need check termination at the demarc box and any splices, but phone devices are notoriously tolerant of polarity reversal.

Yes you can pigtail and splice phone to feed both jacks.

  • This is an old building and i think telephone was later added from the looks of it and they did not even bother with the wires
    – MePo
    Commented Nov 15, 2020 at 15:27
  • 1
    Your jack does appear to be unusual, having an 8P body with center 4 pins conductive, it seems it might be an RJ38x alarm panel jack, which would work for a two wire connection if 1 and 4 aren't used. It is an 8P configuration, but not a typical 8P4C because the wrong pins are present for RJ48 ISDN/T1 . Commented Nov 17, 2020 at 4:09

Your jack plate is not for telephones, it is for internet. It is 8P8C which means "8 pin, 8 conductor" also known as RJ-45. A proper telephone jack is 6P2C or 6P4C, also known as RJ-11. Once you have the proper jack then put the 2 telephone wires to the 2 middle conductors. If the jack shows terrminals 1,2,3,4,5,6 then put the tel line on 3 and 4. It does not matter if blue or white is on pins 3 or 4.

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