In the recent Mr T taxi thread, I mentioned that I had found a way to extend the expiry of my 12call sim card. Several posters asked for details, so I am starting a new thread.
*500*9#(call) will extend the expiration of your sim card by 30 days at a cost of 30 baht. This can be done numerous times to keep extending out the date as far as you need.
A pet peeve of mine is not having phone service when I land at BKK...and I was very tired of having a new phone number each visit. Makes it much more difficult for friends to keep in touch, etc. I usually know when I will be back in Thailand again, so now I just use the above service to make sure I keep the number.
BTW: During my experimenting with Sim cards and services, I Gave True Move a try. Really poor internet service in the Pattaya area. BF confirmed as well, seems 12call is the one to choose in the Pattaya area if you plan on using smart phone / internet service.
If anyone has other tips or codes for 12Call/AIS that they find useful, please post them here. It took me several conversations and trips to different stores to get a good answer and info above, so I would really like to have a thread for sharing these types of things.