I did exactly this when getting FTTP (new FTTP from Zen - questionable choice - 1 month later number to AAISP - great choice, which ceased my FTTC), and it worked well. Definitely worth the upgrade, as once installed and working the FTTP connection is much less likely to require you to troubleshoot issues of connectivity relating to the internet.

It is worth noting that many VOIP providers have very limited options for porting numbers back out of their services, so it pays to research the providers functionality / cost structure meets your requirements prior to doing the deed. You'll be stuck with them for a long time. The VOIP services are much better about accepting new customers and porting in... funny that!

Voipify can only port out to BT:
https://help.voipify.net/knowledge-base/article/port...

I think AAISP are in the same boat, but their website isn't anywhere near as clear (though I recall they tell you during the order process, they could do better here with pre-sales info). There was certainly a time when they had no porting out capabilities at all:
https://www.revk.uk/2012/11/porting-numbers-or-not.html
Best double-check if the ability to port the number back out is important to you.

We just have a forward on the landline number to our mobiles, so our monthly cost with AAISP is basically a couple of quid to retain the old number for the sake of any hospital etc that hasn't got a mobile for us for some reason.

In reply to a post by jimbof:

We just have a forward on the landline number to our mobiles, so our monthly cost with AAISP is basically a couple of quid to retain the old number for the sake of any hospital etc that hasn't got a mobile for us for some reason.

Do you happen to know if AAISP VOIP charge anything for forwarding a number to another number above the cost of the call?
Does the number forward invisible to the caller - ie there is no your call is being forwarded message played?
Is it something you can setup in a control panel so it is under your full control?

Possibly be in a position where I need to sort out a move to an altnet and just in case when I port the old number if I can't get the VOIP to work reliabily if I can just forward the old landline number to a mobile number that will be a good backup?

Thanks

In reply to a post by jimbof:

It is worth noting that many VOIP providers have very limited options for porting numbers back out of their services, so it pays to research the providers functionality / cost structure meets your requirements prior to doing the deed. You'll be stuck with them for a long time. The VOIP services are much better about accepting new customers and porting in... funny that!

I would note that VoIP is still a minefield, and may well 'develop' a great deal in the next couple of years.
I have had two 'problems' with VoIP.
The first was I started a change to Sipgate, this was when they decided to abandon 'Sipgate Basic', luckily I had got a new number, but not ported my old number, as their new charges don't suit my uses. I still use the new number to recieve calls, but who knows what they are going to do with charges or services, they don't seem to be much interested in consumer products.
The second relates to a porting issue. although I had no idea it was that at the time. My phone services and internet have been with TalkTalk Business, I have two lines coming in, copper for the phone, and FTTP for internet, the copper line is not for VoIP, and has a standard cordless plugged in. When I tried to migrate to TalkTalk Consumer there was considerable confusion in TalkTalk, it was found to be 'imposible' to migrate the phone number, I managed to sort out a deal with TalkTalk Business to match the consumer offer, so left it at that. It was only months later that I found out my phone number is somehow listed on TalkTalk Businesses system as a VoIP service and that was why it couldn't be ported, I'm not sure if they have sorted out their systems yet, but serves as a warning that what was once a straight forward system of moving number between providers might not work at the moment for VoIP.
This means if I was to be advising any relatives or friends, I would not suggest moving to a 3rd party VoIP provider unless I was very sure of a companies future plans, as if they go bust or change direction it could mean loss of number.

As far as I'm aware you just get charged their minimum call charge on connection (2.4p inc VAT), and then the per minute fees of 3.33p/minute inc VAT - or whatever applies to the number that gets connected to. If the call lasts exactly 1 minute you should only be charged the minute, if it is more than the minimum call charge. If you forwarded the calls to a landline instead you'd only be charged landline rates. Can also forward to another SIP server.

There is no evidence the call is being forwarded, and the incoming callerID on mobiles appears to be correct (ie you see the caller ID of the original caller, and not some AAISP number). If you wanted to just park the number you could just set their voicemail to receive all calls, play a message and email you the voicemails, and then your cost should be limited to the line rental charge of £1.44.

It's all configured in a control panel. You can set up the forwarding to work alongside the VOIP, so it rings to VOIP and to mobiles (or other landlines) simultaneously, or to delay trying to contact the mobile numbers. You can set it also to record all incoming and outgoing calls if you like, with or without a caller warning. You can also do things like configure which IP addresses are allowed to use SIP on your account to lock down the possibility of fraud.

The AAISP VOIP service works well for my use (and I'm sure it would be sufficient for most users) - I just made the warning about porting out so that people are aware it's not a simple matter if you change your mind with VOIP.

or you can download a sip app for your mobile phone.............

It's much harder to lock down the security of the SIP gateway if you do that.

Security wise, it would be much of muchness for the average user using via a&a to a sip client vs phone forwarding vs sip via ata(standalone or something like the gigaset n510/n300 etc), since weaknesses would appear in any type of device.

Perhaps, but if you're paranoid, and have access to static IPs for your broadband connections that access the SIP gateway, then locking down the IP address is a useful way to end up with an unexpectedly large bill. Wheras to have SIP on mobile, unless you get into a VPN type setup you're going to have to leave the gateway open to any IP address.

More than anything though,, I expect I'm more likely to actually receive the calls with them being forwarded to the mobile number, than if I have to rely both on a data connection of sufficient quality being available via the mobile network, and the SIP client actually being connected.

What a mess this industry has created, I thought Ofcom would help rationalise and standardise, and that 'your right to port your number' was a mandatory requirement?

In reply to a post by aks:

What a mess this industry has created, I thought Ofcom would help rationalise and standardise, and that 'your right to port your number' was a mandatory requirement?

Last week questions where asked in parliament, not about porting but help for vulnerable, apparently BT will now consult further on this.