This information is part of the Modelica Standard Library maintained by the Modelica Association.

DigitalSignal is the basic digital connector definition. A direction (input, output) is not yet defined. DigitalSignal is of type Logic. It can have the logic values (U, X, 0, 1, ...) which are internally coded by integer values by using the enumeration (c.f. the definition of type Logic).

'U'	U Uninitialized
'X'	X Forcing Unknown
'0'	0 Forcing 0
'1'	1 Forcing 1
'Z'	Z High Impedance
'W'	W Weak Unknown
'L'	L Weak 0
'H'	H Weak 1
'-'	- Do not care