Hi,
Simply changing the interrupt declaration from type PBP to ASM makes the latency go from 7.4us to 2.7us (around 40 cycles) with the code in my previous post.
However, if you're going to use assembly interrupts I don't really see the need for DT-Ints. You can not use PBP statements in an interrupt routine declared as ASM (well it IS possible but it's very easy to screw things up and really not recommended).

I don't know what an acceptable error at 2400baud is OR how the bitbanged serial routines in PBP works when being interrupted like that. Apparently it does seem to work the way you currently have it. I guess one way for you to find out is to try.

/Henrik.