You'll be able to use an *unlocked* pre-paid T-Mo phone if it also has the 1800MHz band. FWIW, here in the U.S. the 850/1900 bands are used, but T-Mobile started using 1700 for 3G (while Taiwan uses 2100 for UMTS). Which model do you have btw? Here's a link to Gsmarena with service charts by country-
I am new to t-mobile and their cell phone system.
I just got one prepaid phone from them, and i am wondering if i can use it in Taiwan. Do they use the same phone system?