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Traditional (Centrex) Call Block Feature Activation Instructions

“Call Block” feature on Traditional (Centrex) phone lines

  • Access the Call Block feature by dialing '260' from the handset. (**Note 1)
  • Voice prompted menu navigation is as follows: 

'3' - Toggle Call Block feature on/off. (**Note 2)
'#01#' - Add the last incoming caller to your blocked number list (preferred method)
'#' - Manually add a 10-digit phone number to the blocked number list (**Note 3)
'*' - Remove an entry from the list of blocked numbers
'1' - Verify the list of blocked numbers
'0' - Returns user to menu options

**Note 1 - If you receive a “fast busy” signal immediately after dialing code '260', then contact ISC Client Care for assistance. They must add a telephone feature “SCRJ/Selective Call Rejection” to your phone line.

**Note 2 - You will be prompted to add at least 1 10-digit telephone number to toggle the feature on.

**Note 3 - The system does not allow the manual entry of a 10-digit cell phone numbers. If unable to add it using '#01#', then open a ticket with ISC Client Care and provide the telephone number to be blocked on your handset.

Please contact ISC Client Care online at, by email at, or by phone at 215-898-1000 if you have any additional questions or need assistance with this feature.