ORIGINAL AIRDATE: December 17th, 1990 ---
When sports memorabilia is stolen from the Coltons, MacGyver uncovers a local counterfeiting ring.
MISSION: A ring of counterfeit card makers have their sights on a collection donated by Reggie Jackson and blackmail an aging athlete to steal it for them. MacGyver tracks them down as he attempts to return a box of cards stolen from the Coltons.
This week's highlights include:

Dual-tone multi-frequency signaling (P)

Dual-tone multi-frequency signaling (DTMF) is an in-band telecommunication signaling system using the voice-frequency band over telephone lines between telephone equipment and other communications devices and switching centers. DTMF was first developed in the Bell System in the United States, and became known under the trademark Touch-Tone for use in push-button telephones supplied to telephone customers, starting in 1963. DTMF is standardized by ITU-T Recommendation Q.23. It is also known in the UK as MF4.

Check out the article on wikipedia: https://en.wikipedia.org/wiki/Dual-tone_multi-frequency_signaling.

Watch S6E11: "Squeeze Play" on CBS's website or check the alternative streamability of this episode here.