We've just finished switching our landline phone from Telecom to Vodafone and we asked for voicemail to be activated on the line.

It took me ages to find info on how the voicemail service works, searching on Vodafone's website mostly brings up articles about mobile voicemail, but eventually I found some instructions.  I was surprised that the number used to access voicemail, 083210, is the same as Telecom uses, but I guess it makes sense for all telco's to use the same number.

But what was really surprising is that our pin and welcome message had been transferred over from Telecom, meaning we didn't need to set anything up.

Do the telco's have some sort of arrangement for sharing stuff like this (maybe under the number portability scheme) when people move from one telco to another?