Nortel NTHW25BG 01 4pOC3ChSmIrVsp4E 4-Port OC-3c/STM-1 Channelized ATM FP Card

The Nortel Networks NTHW25BG 01 (designated as 4pOC3ChSmIrVsp4E) is a 4-Port OC-3c/STM-1 Channelized ATM Functional Processor (FP) Card designed for the Nortel Passport MSS 15000 multiservice switching platform. It provides four independent channelized OC-3c/STM-1 (155.52 Mbps) ATM ports with single-mode intermediate-reach (SMIR) optical interfaces, supporting both cell-based ATM switching and channelized TDM mapping capabilities.This line interface module combines ATM VP/VC switching, traffic management, and Quality of Service (QoS) features with channelized functionality, enabling efficient mapping of lower-speed circuits (such as T1/E1 or VT1.5/VC-12) into the OC-3/STM-1 payload. It is optimized for multiservice environments requiring converged ATM, voice, and data services with flexible grooming and interworking. Each port operates at the standard 155.52 Mbps line rate and integrates seamlessly with the Passport 15000 backplane and fabric modules for non-blocking performance.

The NTHW25BG features four single-mode fiber ports with SC duplex connectors, supporting transmission distances up to approximately 15 km over ITU-T G.652 single-mode fiber (SMF). The intermediate-reach (IR) optics make it suitable for metro, regional, and intra-city ATM backbone or aggregation applications. The "Vsp4E" designation indicates enhanced voice service processing or specific firmware/hardware variant for improved voice interworking.

For installation and maintenance, the module occupies a dedicated line card slot in the Passport MSS 15000 chassis. It is a field-replaceable unit with robust backplane connectors. The card operates on standard -48 VDC telecom power and includes front-panel LEDs for per-port link status, activity, alarms, and module health. Proper fiber cleaning and inspection are essential to maintain optimal optical performance.

The card is engineered for carrier-class reliability in central office environments, complying with NEBS-level requirements for electromagnetic compatibility, thermal performance, and high availability. It supports redundant configurations and facilitates fault isolation through built-in diagnostics, loopback testing, and comprehensive system-level monitoring.

During operation, the NTHW25BG continuously monitors port status, ATM cell statistics, channelized traffic, and link quality on all four ports, reporting alarms and performance data to the central control processor. Configuration, traffic engineering, grooming, and firmware updates are managed through the Passport Element Management System or CLI.

The Nortel Networks NTHW25BG 01 4pOC3ChSmIrVsp4E is intended for high-density channelized ATM deployments in the Passport 15000 platform, enabling cost-effective OC-3/STM-1 connectivity with grooming capabilities for voice, video, and data services over single-mode fiber infrastructure in metro and regional multiservice networks.