V1[]
Indications are, TMREAD in SmileBasic V1 is identical to that in V2.
V2[]
TMREAD(string),variableH,variableM,variableS is a command which takes a string representing time (as the TIME$ system variable), and sets the variables to the hours, minutes, and seconds represented by the string.
In particular, the string must be 8 characters long, the third and fifth characters must be ":", and the remaining characters must be digits. The pairs of digits can have any value from 00 to 99, so it will parse strings which do not actually represent a valid time.
See also DTREAD (Command).
V3[]
No information on SmileBasic V3.