SMS on Gigaset C620 phones?

[#1]

I have the Plusnet basic line and fibre package.

Has anybody managed to receive (and send) SMS messages over a BT line? What service centre numbers are you using with your C620? I see this phone has inputs for 4 service centres but only service centre 1 seems to be ticked and can't be changed? I bought the phone used and found 2 received service messages from the previous owner, so it must have worked at some time.

If I send a test message FROM a mobile phone to this landline phone should it be sent as +44 (0) etc etc? To send a SMS test message TO a mobile phone should the number be sent as +44 (0) etc etc or just as the landline number?

I've tried a few service centre numbers, the C620 appears to send them and then locks out getting stuck until a while later when the sent message bounced and shows as 'communication data error'. This makes me think the C620 is doing the right thing but I've got something wrong with the service centre number or my basic line Plusnet package is insufficient for SMS, although I can receive landline calls.

Does Plusnet have their own service centre numbers?

I found this link for BT messaging service centres but I don't understand why there are different service centre numbers for different makes of phone and those I've tried with my C620 don't seem to work.

https://www.bt.com/content/dam/bt/help/legacy-ug/new-pdf/BT%20SMS%20Text%20service%20centre%20number...

[#2]

Well, I've tried everything and I can only get a robot text to voice conversion from a mobile phone text sent to my landline phone. I rang the BT 0800 number for SMS info. It told me my CLID was blocked (Plusnet default?) so I redialed with a 1470 prefix, my landline number was confirmed and I got the BT automated message where I could change the curtain time.I have noticed SMS service centre access numbers are preceded by 1470P.

The BT text to voice doesn't use SMS service number access so I'm now thinking there's no SMS gateway between Plusnet and BT for SMS, unless I need to pay for a package of some sort? I'm o.k paying for an outgoing SMS with free incoming, but suspect there may not be a Plusnet payment structure setup for it?

Some may wonder why I'm bothering with SMS on landline? If you ever have to switch your cordless line phones to another brand and have to transfer you contacts and blocking lists (which may be huge), the only way is to export or import a vCard list via SMS, or spend a long time with your fingers rebuilding it on a handset. Thank goodness for Android and Apple!

Fortunately, I have a hard to find cordless GSM mobile setup and my landline calls are already moving from BT to a mobile service provider.

Has any member on Plusnet been able to receive a text messages as text on their SMS enabled landline phone?