This discussion topic has been answered Discussion topic: SR203 Router Purple socket vs Yellow socket no. 4
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Message posted on 24 Nov 2025 04:51 PM
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Getting ready for activation tomorrow and instructions say use yellow no. 4 for connection to ONT.
So what is the purple socket for?
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Message posted on 24 Nov 2025 07:35 PM - last edited: 24 Nov 2025 07:46 PM
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@David382 wrote:
So I think what your answer means the yellow no. 4 is for full fibre as I have and the purple was for when a couple of years back pre full fibre and copper wires were to my house.
That's correct.
Shame the purple can't be used as I would have liked to have used yellow no. 4 along with 1 to 3 for ethernet connections.
It's not physically or logically possible to route ethernet from an ONT into a modem socket: they are talking different languages. An unmanaged gigabit ethernet switch is the appropriate hardware to provide additional RJ45 ports.
Lets hope the next design of router has a seperate WAN socket to give back 4 sockets to use when copper wires for BB/telephone were in use.
That will typically be the case as FTTP speed increases: the Sky Gigafast+ Hub for 2.5Gbs and 5Gbs over CityFibre infrastructure has a 10Gbs WAN port for the ONT plus four ethernet ports (1x10Gbs and 3x1Gbs)
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BT Halo 3+ Ultrafast FTTP (500Mbs), BT Smart Hub 2
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Message posted on 24 Nov 2025 06:00 PM - last edited: 24 Nov 2025 06:05 PM
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Re: SR203 Router Purple socket vs Yellow socket no. 4
@David382 wrote:
So what is the purple socket for?
An RJ11 connection from a 'phone' socket for ADSL, FTTC and (possibly ) G.fast broadband i.e. metallic circuits. It goes to a VDSL modem chipset within the Hub.
This isn't required for FTTP because it's the ONT which performs the 'modem' (or more accurately transponder) function.
BT Halo 3+ Ultrafast FTTP (500Mbs), BT Smart Hub 2
Message posted on 24 Nov 2025 06:29 PM
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Re: SR203 Router Purple socket vs Yellow socket no. 4
So I think what your answer means the yellow no. 4 is for full fibre as I have and the purple was for when a couple of years back pre full fibre and copper wires were to my house.
Shame the purple can't be used as I would have liked to have used yellow no. 4 along with 1 to 3 for ethernet connections.
Lets hope the next design of router has a seperate WAN socket to give back 4 sockets to use when copper wires for BB/telephone were in use.
Thanks for your answer.
Message posted on 24 Nov 2025 07:35 PM - last edited: 24 Nov 2025 07:46 PM
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@David382 wrote:
So I think what your answer means the yellow no. 4 is for full fibre as I have and the purple was for when a couple of years back pre full fibre and copper wires were to my house.
That's correct.
Shame the purple can't be used as I would have liked to have used yellow no. 4 along with 1 to 3 for ethernet connections.
It's not physically or logically possible to route ethernet from an ONT into a modem socket: they are talking different languages. An unmanaged gigabit ethernet switch is the appropriate hardware to provide additional RJ45 ports.
Lets hope the next design of router has a seperate WAN socket to give back 4 sockets to use when copper wires for BB/telephone were in use.
That will typically be the case as FTTP speed increases: the Sky Gigafast+ Hub for 2.5Gbs and 5Gbs over CityFibre infrastructure has a 10Gbs WAN port for the ONT plus four ethernet ports (1x10Gbs and 3x1Gbs)
![]()
BT Halo 3+ Ultrafast FTTP (500Mbs), BT Smart Hub 2
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