2 9,953.28 Mbps STM-64 reached specified a basic transmission rate of 51 Mbps for SONET and a basic rate of 155 Mbps for SDH. SONET and SDH converge at SDH's 155- Mbps base level, which is defined as Synchronous Transport Module-1 (STM-1). The base level for SONET is STS-1 (or OC-1) and is equivalent to 51.84 Mbps. Thus, SDH's STM-1 is equivalent to SONET's STS-3 (3x51.84 Mbps = 155.5 Mbps). Higher SDH rates of STM-4 (622 Mbps), STM-16 (2.4 Gbps), and STM-64 (9.9 Gbps) are also defined (see Table 3-2). 3.3 Standards Details This section contains some key information from the baseline SONET standard. The basic standard of interest is ANSI T1.416-1999, "Network to Customer Installation Interfaces-Synchronous Optical NETwork (SONET) Physical Layer Specification: Common Criteria." The standard establishes common criteria for SONET interfaces at standard rates asso- ciated with the network interface (NI). Covered herein are maintenance and operation functionality at the SONET section-, line-, and path-layer specifi- cations. Other necessary criteria for compliance with the proper interfacing of the connecting customer installation (CI) equipment are found in the other document of this series. Compliance with this standard addresses net- work and customer installation compatibility and is not to be construed as a constraint on the internal operations of the network or the customer Chapter 3 installation equipment. Other documents included in the ANSI T1.416 series are listed in the following: ANSI T1.416.01-1999, "Telecommunications-Networl to Customer Installation Interfaces-Synchronous Optical NETwork (SONET) Physical Media Dependent Specification: Multi-Mode Fiber" ANSI T1.416.02-1999, "Telecommunications-Network to Customer Installation Interfaces-Synchronous Optical NETwork (SONET) Physical Media Dependent Specification: Single-Mode Fiber" ANSI T1.416.03-1999, "Telecommunications-Network to Customer Installation Interfaces-Synchronous Optical NETwork (SONET) Physical Media Dependent Specification: Electrical" The 