Source : Free On-Line Dictionary of Computing

Gunning Transceiver Logic
     
         (GTL) A
        {standard} for electrical signals in {CMOS} circuits used to
        provide higher data transfer speeds with smaller voltage
        swings [compared with what?].
     
        The GTL signal swings between 0.4 volts and 1.2 volts with a
        reference voltage of about 0.8 volts.  Only a small deviation
        of 0.4 volts (or thereabouts) from the reference voltage is
        required to switch between on and off states.  Therefore, a
        GTL signal is said to be a low voltage swing logic signal.
     
        Gunning Transceiver Logic has several advantages.  The
        {resistive termination} of a GTL signal provides a clean
        signalling environment [what?].  Moreover, the low terminating
        voltage of 1.2 volts results in reduced voltage drops across
        the resistive elements.  GTL has low power dissipation and can
        operate at high frequency and causes less {electromagnetic
        interference} (EMI).
     
        {GTL/BTL: A Low-Swing Solution for High-Speed Digital Logic
        (http://www.edtn.com/scribe/reference/appnotes/md003ecc.htm)}.
     
        (2000-01-16)