removing digits on CID for incoming calls

Clean CID Number -This field allows you to specify a number of digits to restrict the incoming caller ID number to by putting an R in front of the number of digits, for example to restrict to the right 10 digits you would enter in R10. You can also use this feature to remove only a leading digit or digits by putting an L in front of the specific digits that you want to remove, for example to remove a 1 as the first digit you would enter in L1. Default is empty. If more than one rule is specified make sure you separate them with a space and the R will run before the L. 

ON DID settings