Time Convert
If value "1234" is in cell A1, put this formula in B1. =TIME(0,LEFT(A1,2),RIGHT(A1,2))
Format cell B1 to TIME and select format 13:30:55.
Note the formula assumes you always have a four-digit number to convert and that the first two digits are always minutes, last two always seconds. If this is not the case, such as a three-digit value like 930, the formula can be adjusted with an IF statement to take the minutes from the first digit only:
=IF(LEN(A1)=3,TIME(0,LEFT(A1,1),RIGHT(A1,2)),TIME(0,LEFT(A1,2),RIGHT(A1,2)))
Also, the result gives hours:min:sec, and since there are no hours, it comes out to 0:12:34. There are ways to get rid of the zero hours.
It's not the coding solution you asked for but I'm sure someone can combine the formula with other bits of coding to take advantage of it, or a coding only method to directly translate.