1) An old-fashioned
telecommunications device that makes digitally-encoded sounds to be received
and interpreted through a telephone handset. The acoustic coupler had two rubber cups
that fitted the "mouthpiece" and "earpiece of an old-fashioned phone
2) A person who makes a lot of noise during sex.
"My phone won't fit the rubber cups on this
"Britney had her boyfriend round overnight
and I couldn't get to sleep. She's such an acoustic coupler"