Siemens 600 Series - Manual (Page 80)

3–16 ROLMphone 300/600 User Guide
Direct Trunk Select
Direct Trunk Select lets you choose a particular trunk
(outside line) for placing a call.
To choose a
trunk ➩ Get a dial tone.
➩ Press the Direct Trunk Select (DTS) key, or dial
# # 8.
➩ Dial the number assigned at the CBX for the
specific trunk you want.
➩ Dial the outside number.