Nortel ST3150N 120MB Disk Drive

The Nortel Networks ST3150N is a 120 MB hard disk drive (HDD) originally supplied as part of the NT7P43AA kit for the DPN-100 packet switching platform (also known as SL-10 in some configurations). It serves as a storage module for system software, configuration data, logging, and operational databases in legacy Nortel packet network nodes.This disk drive is designed for integration into DPN-100 / SL-10 shelves or processor cards that require local non-volatile storage. It provides the necessary capacity for booting the node, storing routing tables, X.25/Frame Relay configuration files, and maintaining accounting or diagnostic records typical of early packet-switched data networks.
The ST3150N uses a standard 3.5-inch or proprietary form factor compatible with the DPN-100 hardware architecture, with an interface tailored for the platform’s backplane or controller card (commonly IDE/PATA-like or proprietary parallel interface used in that era). It operates at standard rotational speeds for 1990s-era drives, delivering sufficient I/O performance for control-plane and low-volume data storage requirements in carrier or enterprise environments.
Key characteristics include a formatted capacity of 120 MB, support for the DPN-100 file system and boot procedures, and robust mechanical design rated for continuous operation in central office conditions. The drive is intended for use in redundant or single configurations depending on the specific DPN-100 node type (processor shelf, switching node, or remote packet device).
Environmentally, the ST3150N is engineered for telecom deployment, operating within typical central office temperature ranges (0°C to +45°C) and humidity levels up to 95% non-condensing when installed inside the protected shelf enclosure. Power is supplied directly from the host card or shelf backplane at standard +5 V / +12 V DC rails common to that generation of equipment.
In deployment, the disk is installed in the designated drive bay or slot of the DPN-100 processor module. It pairs with compatible system controllers and requires proper formatting and software loading during node commissioning or recovery procedures. The drive supports standard Nortel maintenance commands for disk diagnostics, backup, and restore operations through the SL-10 / DPN-100 element management or craft interface.
Maintenance involves periodic monitoring of disk health via system logs and error counters, verification of read/write functionality during scheduled outages, and replacement when bad sectors or mechanical failure occurs. As a rotating media storage device, it has a limited service life and is considered a consumable spare part in legacy DPN-100 installations still in operation.
The ST3150N / NT7P43AA kit complies with the original Nortel specifications for electromagnetic compatibility and safety within the DPN-100 platform. This HDD enables continued operation and cost-effective maintenance of legacy Nortel packet switching systems still in service in certain operator or industrial networks, providing essential local storage without requiring full platform migration.