This read-write value controls whether the ATM cell scrambler is turned on for interfaces carrying ATM over DS3 or E3, and automatically reads back as notSupported on interfaces that don't do ATM at all. Engineers enable scrambling to prevent long runs of repetitive bit patterns in ATM cells from causing clock-recovery or line-coding problems on the physical link. On an ATM-over-DS3 interface experiencing intermittent bit errors tied to certain traffic patterns, setting this to scramblerOn(1) is a standard fix.