I have the Casio PCR-2100 and I wanted to know if anyone knew a better way of loggin in and out of a clerk, and also how to use the Clerk Secret Number.
I've tried to use the Clerk Secret Number and had to reset the register because I couldn't fathom how to login.

What I do is:

-Key to Program
3 SUBTOTAL
<Desired Clerk #>
Press CLERK # key
SUBTOTAL
-Key to REG

I cannot Just go into REG, Type in a Clerk # then, Hit the Clerk Key, I get one solid loud tone every time.

seems like your missing a step

-Key to program
-3
-SUBTOTAL
<Desired Clerk #> "01,02,03,04" etc.
then 07 for example "0107" for clerk #1
-SUBTOTAL
then you input a 4 digit code
-CA/AMT/TEND
-SUBTOTAL