Digital Lightwave Inc. C9 ATM (Asynchronous Transfer Mode) NOTE: This module is a daughter board for MSA 2020/2030 or SSA 1220 module (required) Supports ATM testing within following containers, if supported by the MSA or SSA module: " STS12c, STS3c, STS1, AU4-4c, AU4, AU3, VC2,