IBM AT 5170 Technical Reference page 447

Glossary
This glossary includes definitions developed by the American
National Standards Institute (ANSI) and the International
Organization for Standardization (ISO). This material is
reproduced from the American National Dictionary for Information
Processing, copyright 1977 by the Computer and Business
Equipment Manufacturers Association, copies of which may be
purchased from the American National Standards Institute, 1430
Broadway, New York, New York 10018.
JL.
Prefix micro; 0.000001.
JLS.
Microsecond; 0.000001 second.
A. Ampere.
ac. Alternating current.
accumulator. A register in which the result of an operation is
formed.
active
high.
Designates a signal that has to go high to produce an
effect. Synonymous with positive true.
active low. Designates a signal that has to go low to produce an
effect. Synonymous with negative true.
~ adapter. An auxiliary device or unit used to extend the operation
of another system.
Glossary-l