NEC DS1000 Feature Handbook page 24

Central Office Calls, Placing
To place a call over a line group (using a Line Group
Access Code or Line Group Routing):
Standard Operation
1. Press
2. Dial a Line Group Access Code (90-98).
3. Dial the outside number you want to call.
18
.
Dial 90 for group 0, 91 for group 1, etc.
If you hear dial tone as soon as you dial 9, your
system has Line Group Routing. (A line group has
been automatically selected for you.)
Toll Restriction may prevent you from dialing cer-
tain outside numbers.
If you use a dial pulse line and wait 6 seconds
after dialing a digit, the system outdials any remain-
ing digits as DTMF.