Apple has posted a new tech document explaining the differences between GSM and CDMA models of its iPhone 4.

[ad#Google Adsense 300×250 in story]The CDMA version of the iPhone 4 made its debut in the United States on Verizon’s network earlier this month. The GSM version is sold worldwide, and sold by AT&T in the United States.

While the phones are physically similar and run the same applications downloaded from the App Store, there are some distinct operational differences in how they act as phones, according to Apple.

Apple’s notes include a table to more easily distinguish the differences in features such as call waiting, call forwarding, conference calls and putting calls on hold.

Overall, AT&T’s GSM iPhone 4 comes out looking a bit better – GSM iPhones, for example, can support up to five calls for conference calls simultaneously, while CDMA phones have a hard two call limit. Callers using GSM phones can place calls on hold, while CDMA iPhone users can’t. What’s more, Apple notes that CDMA networks “may not be able to add, swap, or merge calls in certain situations.”

Hat tip: 9to5Mac