For each exchange, the telephone numbers were formed by random digits, thus including both listed and unlisted numbers.
Within each exchange, random digits were added to form a complete telephone number to permit access both to listed and unlisted numbers.
Earlier I watched him recite a list of 252 random digits as effortlessly as if it were his telephone number.
A random digit chart is simply a large table of random digits.
A one-time pad uses a keystream of completely random digits.
Watching him, she mechanically punched out random digits and listened.
The telephone numbers were formed by random digits, thus including both listed and unlisted numbers.
Here is an example of code that will print 4 random digits.
Within each exchange, random digits were added to form a full telephone number, thus allowing access to listed and unlisted numbers.
Some modern tests plot random digits as points on a three-dimensional plane, which can then be rotated to look for hidden patterns.