Why are we limited to a max of 30s before O2 Voicemail kicks in?

[Tawnydun]

I need longer. 30 seconds is often insufficient time for me to get to my mobile and I invariably miss many calls because I reach the phone and Voicemail has already kicked in and my caller hung up. It’s bloody annoying. Why can’t we choose how many rings or set how many seconds the delay is, rather than being arbitrarily set to a 30s max? It makes no sense. I’ve had to completely disable my O2 Voicemail because I was losing too many calls. Thanks O2. 😕

[MI5 · Accepted solution]

@Tawnydun 

It's a GSM standard that is the same on all networks.

As you say, if you need longer, you need to turn off voicemail.

[jonsie]

Unfortunately that is the maximum time you can have unless of course you switch off completely. There is no 'in between', it's one or the other. As far as I know all networks have the same type of MSISDN code to use with thirty seconds as a maximum.

[Tawnydun]

Many thanks for the quick replies. 👍🏻

Is there any genuine technical reason for the 30s max or is it just a case that someone decided that would be an okay default and that’s just that? Just curious really, since I can’t be the only one frustrated by this, across the networks. 

[MI5]

Somebody somewhere thought it was a good idea to limit it to 30 seconds right back at the very beginning of GSM phone networks.
No doubt it was to reduce load on the networks back then but probably no good reason these days.
However, there are noise pollution laws which limit things like car alarms and house alarms so it's possible that phones fall into a similar category.