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21cv phone connecting through virgin router, but to use analog alarm system

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Hello, we recently had our Virgin phone system moved from our wall sockets to the router. This is a problem because our alarm system was hardwired into those sockets. We had an engineer for the alarm company visit and tell us we need to pay over £1000 to upgrade our alarm system to become "digital". I am wondering if this is a sales ploy and instead we could just get the alarm working by running a cable to the router. I do not want to run the cable yet unless I know for sure it's going to work. So my question is, does the connector on the back of the router support analog signals? If I put a splitter on the back of the router, could I run a separate cable to an analog device? He was saying that phones will all become digital and analog phones won't work, but he was talking about BT specifically, does this also apply to Virgin? I would really appreciate some advice.


Forum Team
Forum Team

Hey rosskiwrongun, thank you for reaching out and I am sorry you are having some issues with the 21CV phone system.

As it stands 21cv is all digital only and no copper wire, the phone will go into the back of the router.

I can confirm that the adaptor does not support analogue  and only digital only sorry. 

By 2025 he is correct in saying this at Virgin all phones will be digital only.

You can find out more about this here Thanks. 

Matt - Forum Team

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Alessandro Volta

@rosskiwrongun wrote:

Hello, we recently had our Virgin phone system moved from our wall sockets to the router. This is a problem because our alarm system was hardwired into those sockets. <snip>

Your easiest way to test your alarm functionality would be to buy a pre-made phone extension cable of a suitable length (with a moulded plug and socket on the ends, available from DIY shops etc.). For the purposes of a test, temporarily hook this up to your alarm and connect to the VM phone socket on the hub. Test the alarm and see if it is able to dial out over the VM 21CV phone line.

Whether the alarm works or not might depend on what kind of signal the alarm is trying to send out. There was a recent past topic where the customer's alarm panel was trying to send data to a SMS service which would, in turn, text the customer that the alarm had been triggered. This didn't work over the new 21CV phone connection. The phone connection on the back of the hub it not a true VOIP connection. It is designed to behave like an ordinary telephone socket. A simple speech dialler in the alarm panel may work. An alarm output transmitting data may not.

If you do a temporary test as above, and find your system can dial out over the 21CV connection, then VM should modify your home phone wiring, free of charge, to link the alarm panel to your 21CV phone connection.

Worth noting though that the phone connection from the VM hub will only be able to dial out if the hub is functional so, if your alarm is triggered during a power cut for example, the alarm would not be able to dial out.

Your alternative option to dialling out over the 21CV phone connection would be to use a mobile connection for the alarm to dial out, or a fail-over setup so if the hub's phone line is down the alarm will switch to an alternative mobile connection. Some alarms will have an add-on feature to install a comm's card with additional comm's features. Some may need an add-on device.

£1000 to modify your existing system sounds like a lot of money to me for such work. Maybe you should get a second opinion from another alarm company as to the costs involved if you determine that you do need the work doing.