TTL(i) or CMOS for interfacing to PIC?

Hi all, I'm new here but i have been playing with PICs for a while and have completed a few good projects so i'm not a total n00b.

In my latest venture I am trying to interface an Innovations ID12 rfid tag reader to a 12f629.

Now, the ID12 has 2 outputs, one is 'CMOS' and the other is 'TTL (Inverted)'

I perhaps wrongly assumed that CMOS would be the connection of preference but although i receive data, it seems incorrect. The data being fed to the PIC is no where near what it says it should be in the spec sheet and is inconsistent.

The reason i went with this method is that looking at code posted on this forum for talking to the ID12 did not allow for inverted serial data. Perhaps the serin(2) commands expect it inverted to start with??? I spose that makes sense...
Example: http://www.picbasic.co.uk/forum/show...highlight=RFID



I know that Inverted TTL is like a pseudo RS232 and assumed that was more for connecting it directly to a PC.

Should i perhaps be using the inverted TTL for connection to the PIC? If so, what/when would you use the CMOS output?

Thanks in advance...