Bell System Prefixes

Bell System Prefixes are the various prefixes used throughout the Bell System to refer to documentation, drawings, and specifications.

BLR: Bell Labs Record; a report by Bell Labs which invented new technologies for the Bell System.

BSP: Bell System Practice; step by step instructions for operation and recovery from equipment errors and issues.

KS: (abbreviation unknown); schematic made by Western Electric for implementation by another company.

SD: Schematic Drawing; a wiring diagram for a specific component of a device.

External Links

• The Telecom Archive (contains several Bell System resources that make use of these prefixes)