Differences between em4305 and t5577?

Hi. Can someone explain me differences between t5577 and em4305 ? Yes I know t5577 more expensive and better quality. But why do all sellers describe their items as “keyfob t5577/em4305”. Am I right that t5577 and em4305 is not the same thing?
For now i need to buy t5577 about 100pcs. How i can be sure that item is really t5577 and not 4305 ? What do i have to ask seller or where I can order T5577 ? Thanks

The T5577 is an emulator chip, T5577/EM4305 may mean that they are selling T5577 chips that come pre-configured in EM4305 mode, that would be my guess anyways

The T5577 doesn’t do a whole lot when it’s blank, which leads to people thinking something is wrong with their chip when all they need to do is write some data to it. To prevent this, I imagine some sellers just ship the chips pre-configured as something


Yep this was my experience when I got some T5577s to test things with after I got my NExT. Wouldn’t even beep on a reader but as soon as I wrote data to it, it sprung to life and worked exactly as you’d expect.


Oh to have faith in Chinese humanity. There’s typically no such logic behind product listings posted by Chinese companies. I’m only assuming here that the product is being sold by a Chinese company, but it sounds like it to me just because of the ambiguity. The EM4305 is also a read/write chip similar to the t5577 but it doesn’t perform emulation of other analog front ends.

Because of this I would contact the seller and ask specifically if it is an EM or T5 chip.