Vibratese

[1] Vibratese was initially developed as a potential avenue to transmit intelligence to military targets in compromising environments.

[3][4] Geldard identified three tactile dimensions that could be easily and quickly discerned by an interpreter: duration, intensity, and location.

Morse code is an example of an auditory system which transmits information modulated by duration alone, and can be used in a tactile device.

This allowed for a theoretical maximum transmission rate of 67 words per minute, versus Morse code with about 30.

[1] Additionally, Geldard proposed a potential system using closely spaced vibrators which could transmit focal movements, like the tracing of a finger, on the subject.