I just purchased a Coby TV Model number TFTV 3255. I am very happy with the set. However it has only ONE audio output. The manual, on page 7, "coaxial output" ,an optical audio cable is required. the back of the TFTV 3255 looks like a Digital cable, RCA type. Every cable I have looked at in the stores in my location, Long Island, NY., do not have a optical cable that will interface will my tv. SO WHICH CABLE IS IT? Thank YOU for your time.

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I also have a Coby TV and it's the instructions that are at fault.
They say:
"When MPEG audio or Dolby Digital audio is played, Dolby Digital bitstream or MPEG audio bitstream is sent to the player's digital audio output connector. When the player is connected to a Dolby or MPEG audio decoder via this output socket, you can enjoy theater-quality audio in your home. An optical audio cable is required when a Dolby Digital decoder or MPEG audio decoder is used. The mentioned cable is not included with this product."
Huh. Talking out of both sides of their audio connection.
If the output connector on the tv is orange like mine, it's digital audio and you need a digital audio input connector on your home theater. You can also buy converters to go from digital audio to optical (also called toslink).
Perhaps that's what Coby's Chinese translators meant to say.

If it is a single output and looks like an RCA type, then I would say that the cable you would need is a digital coaxial cable. The optical input/output will have a different shape and is not as big of an opening as a digital coaxial input/output.