VOIP on T-Mobile web and walk

[leaky5]

If you create a VPN from a PC with a T-Mobile data card to say a Draytek VPN / VOIP router. Would T-Mobile be able to tell if you are running VOIP over that link ? My guess would be no, as the VPN source would be an application on the laptop and not the data card. I was wondering if anyone else had tried this.

[devoiddroid]

I thought the issue was with the amount of data you use rather than what you use it for?

[leaky5]

Web n Walk Max includes VOIP, but is abour £14 a month more than the standard Web n Walk