It's not just the ring type. If it's going to voicemail too quickly after that, then it's a setting your servicer provider (eg Vodafone) controls.
I've long suspected that they keep the default ring time very short so that they maximize revenue from people forced to call their mailbox, simply because they did not answer their phone fast enough. They also make no money whilst your phone is signalling (ie ringing), but not in a voice call, so there is more pressure on them to minimize the ringing periods, especially where networks are busy.
If you call your provider (Vodafone or whoever), they should have a setting they can give you to set the ringing time for longer. I did it and needed to key in a control string involving lots of control characters. I got it out to 40 seconds once.