Standard Modular System: Difference between revisions

Revision as of 23:08, 15 June 2011

Revision as of 04:04, 30 August 2011

Line 6:

Many IBM peripheral devices that were part of System/360, but were adapted from second-generation designs, continued to use SMS circuitry instead of the newer SLT. These included the 240x-series tape drives and controllers, the 2540 card reader/punch and 1403N1 printer, and the 2821 Integrated Control Unit for the 1403 and 2540. A few SMS cards used in System/360 peripheral devices even had SLT-type hybrid IC's mounted on them.

SMS cards were constructed of individual [[discrete component]]s mounted on single sided paper-epoxy [[printed circuit board]] boardss. Single width cards were 2.5 inches wide by 4.5 inches tall by 0.056 inches thick, with a 16 pin [[gold]] plated [[edge connector]]. Double width cards were 5.375 inches wide by 4.5 inches tall, with two 16 pin gold plated edge connectors. Contacts were labeled ''A–R'' (skipping ''I'' and ''O'') on the first edge connector, and ''S–Z, 1–8'' on the second.

The cards were plugged into a card-cage back-plane and edge connector pins connected to wire-wrap pins. All interconnections were made with wire-wrapped connections, except for power buss lines. The back-plane wire-wrap connections were mostly made at the factory with automated equipment, but the wire-wrap technology facilitated field-installation of engineering changes by customer engineers.