: (ps2kcB) ( for port B )
	( Port B TL is bit 2 )
    _D2@ 0x04 AND IF 0 EXIT ( nothing ) THEN
    0 _THB! ( Port B TH output, low )
    _D1@ ( bit 7:6 go in 1:0 ) 6 RSHIFT ( n )
    _D2@ ( bit 1:0 go in 3:2 ) 0x03 AND 2 LSHIFT OR ( n )
    1 _THB! ( Port B TH output, high )
    _D1@ ( bit 7:6 go in 5:4 ) 0xc0 AND 2 RSHIFT OR ( n )
    _D2@ ( bit 1:0 go in 7:6 ) 0x03 AND 6 LSHIFT OR ( n )
	2 _THB! ( TH input ) ;