Vertical Communications DSU and DSU II - Manual (Page 51)

Making Calls
4.1 Dialing Manually
You can manually dial a number over a selected telephone line. Or, if
your telephone was given a prime line or idle line preference feature
when it was installed, it will automatically select a line for your use
when you lift the handset.
•
To dial an outside number manually,
1. Press line button to select line (remember—selecting a line is not
necessary if a prime line or idle line preference feature has been
assigned to your telephone and if you lift the handset to begin the
call).
2. Listen for dial tone.
3. Dial number.
4
GCA70–245 Making Calls
LCD Speakerphone Reference Manual 4–1