DESCRIPTION
The PM7340 S/UNI-IMA-8 is a monolithic integrated circuit that implements the Inverse Multiplexing for ATM (IMA 1.1) protocol with backward compatibility to IMA 1.0 and the Transmission Convergence (TC) layer function.

FEATURES
The PM7340 S/UNI-IMA-8 is a monolithic integrated circuit that implements the Inverse Multiplexing for ATM (IMA 1.1) protocol with backward compatibility to IMA 1.0 and the Transmission Convergence (TC) layer function. The S/UNIIMA-8 supports 8 T1, E1 or unchannelized links where each link is dynamically configurable to support either IMA 1.1, backward compatible IMA 1.0, ATM over T1/E1, ATM over fractional T1/E1 or ATM HEC cell delination for unchannelized links Unchannelized links may be used to support applications such as ADSL.

Standards Supported
• ATM Forum Inverse Multiplexing for ATM Specification Version 1.1, March 1999
• ATM Forum Inverse Multiplexing for ATM Specification Version 1.0 – supports the method of reporting Rx cell information as in Appendix C.8 of the ATM Forum Inverse Multiplexing for ATM Specification Version 1.1 for symmetrical configurations with M=128.
• I.432-1 B-ISDN user network interface – Physical Layer specification: General characteristics
• I.432-3 B-ISDN user network interface – Physical Layer specification: 1544 kbps and 2048 kbps operation
• ATM on Fractional E1/T1, af-phy-0130.00 October, 1999

IMA Features
• IMA 1.1 protocol including group and link state machines implemented by on-chip hardware.
• Supports up to 4 simultaneous IMA groups.
• Each IMA group can support any number of supported links.
• Each link can be programmed for either IMA processing or cell delineation.
• Supports all IMA Group Symmetry modes:
   • Symmetrical configuration with symmetrical operation
   • Symmetrical configuration with asymmetrical operation.
   • Asymmetrical configuration with asymmetrical operation.
• Performs IMA differential delay calculation and synchronization.
• Provides programmable limit on allowable differential delay and minimum number of links per group.
• Supports up to 279 ms (for T1 links) and 226 ms (for E1 links) link-differential delay between links in an IMA group.
• Performs ICP and stuff-cell insertion and removal.
• Supports both Common Transmit Clock (CTC) and Independent Transmit Clock (ITC) transmit ICP stuffing modes.
• Supports IMA frame length (M) equal to 32, 64, 128, or 256.
• Optionally supports the IMA 1.0 method of reporting Rx cell information as defined in appendix C.8 of the ATM Forum Inverse Multiplexing for ATM Specification Version 1.1 for symmetrical configurations with M=128.
• Provides IMA layer statistic counts and alarms for support of IMA Performance and Failure Alarm Monitoring and MIB support.
• Provides per link counters for statistics and performance monitoring:
   • ICP Violations
   • OIF anomalies
   • Rx Link stuff events
   • Tx Link stuff events
   • User cells
   • Filler cells
• Provides per group counters for statistics and performance monitoring:
   • User cells received
   • Filler cells received
   • User cells transmitted
   • Filler cells transmitted

APPLICATIONS
• Digital Subscriber Line Access Multiplexers (DSLAMs)
• Access Concentrators
• Integrated Access Devices (IAD)
• Wireless Base Transceiver Stations