I have AIS Unlimited Data at the moment but my circumstances have changed and I want to change packages but don't understand the Data signal types, as AIS offer different packages. I would be grateful if someone could give a layman's explanation about the different types I've heard of. I know about 3G but I see 'Edge' most of the time on my data signal and then there are times I see 'H' in say Chiang Mai or Bangkok.

AIS have data packages that have Edge only as well as (3G and Edge). I'm wondering what happens if I have an Edge only package and go to a 3G signal area; would I get stiffed for the 3G 'Per Minute' charge?

I never used a data connection prior to coming to Thailand. I've been contemplating how people use say the Megabyte download limit versus the Hourly limit. It sounds difficult to know how many MB as each page is different. It sounds easier to roughly remember how many hours I've used. Having said that, does AIS give a facility to keep an eye on what you've used eg a free * number?

Can you share any details? Primary location(s) in Thailand, type of phone? budget? usage? applications?

Generally speaking a volume-based plan is better than a time-based plan. Based your phone's specs you would choose a service provider who offers 3G, and perhaps ancillary WiFi services, for those areas in Thailand you frequent.

With more details we can fashion some suggestions.

http://www.ais.co.th/mobileinternet/en/internet-package/

Note the time, volume and calculator tabs.

Many thanks for your help and apologies for replying later than I'd hope.

I live in the north but do venture out about 2 or 3 days a month to Chiang Mai and Bangkok. I have a Samsung Galaxy S2. In terms of budget I just want to reduce from the 650 Baht unlimited at the moment as I don't use it as much as I thought I would. I'm looking to use wifi from my home connection along with any hotspots etc out and about. I'm thinking that I'll be needing a 2/3G connection for about 20 or 30 hours a month based on average usage. Looking at the charts you linked - I guess I could try the 100 Baht(20 hours). I could then perhaps try the 99 Baht (75Mb) afterwards and compare.

Maybe try a program like Droidstats to monitor your usage; after a few months you can get a feel for your requirements.

Generally I'd recommend a volume-based plan; the 1 GB/350 baht hits the sweet-spot for many.