To test your system, you will need a multitester, which checks voltage and continuity. VIEW E-EDITION. 25¢ for 3 mos. Support local journalism. Only 25¢ for 3 months. MANAGE ACTIVATE SIGN IN. Hi .

For his teaching machine (known to him as the multitester), Joseph Ray used long strips of cardboard with twenty pairs of words or pairs of images written or drawn on one side. Occasionally there also ...