Zoom ISDN TA/V.34 Owner's Manual page 6

We occasionally insert spaces between commands to make a command
line easier to read. You can type the command line with or without
spaces between commands as long as the command line does not
exceed 255 characters (spaces count as characters).
•
The letter "O" is always shown in lower case (o or o) in a command
line. The number zero is always shown as "0."
6 TA/V.34 and TA Owner' s Manual