That sounds as if you have a second master socket rather than an extension socket.
Yes, I have read your other thread, but I still think that cordless phones are a much better and simpler solution than trying to accommodate fixed phones and bells.
Not wishing to be rude, but if your wife struggles to hear anything other than a very loud bells I'm not sure I understand how she can hold a phone conversation in any case.
Personally, I find that using my mobile via my hearing aids with Bluetooth is a far superior method of holding a conversation than trying to use the landline.
