IP Phone User Manual
1.5 Making Call Features
84 Feature Guide
1.5.5.3 Trunk Access
Description
There are the following features to access a trunk.
Conditions
• COS programming determines the trunk groups available for making calls (  Trunk Group 
Number [500]).
• Trunk numbers can be referred on a trunk port basis (  LCOT/BRI Trunk Number 
Reference [409]).
• Button Assignment
A flexible button can be customised as a G-CO, L-CO, or S-CO button as follows:
It is possible to assign trunks in the following ways:
Dialling the Trunk Access number selects a CO button according to the priority: S-CO   
G-CO L-CO
• Direct Trunk Access
By pressing an idle CO button, it automatically switches on the hands-free operation mode 
and allows a user to use On-hook Dialling. The user need not press the SP-PHONE 
button, MONITOR button, or lift the handset.
• Group Hunting Order for Idle Line Access
An idle trunk is selected from the trunk groups assigned for Idle Line Access. If multiple 
trunk groups are available, the trunk group hunting sequence can be determined through 
system programming.
Feature Description Accessing method
Idle Line 
Access (Local 
Access)
Selects an idle trunk 
automatically from the assigned 
trunk groups.
Dial the Idle Line Access number. Or 
press a L-CO button.
Trunk Group 
Access
Selects an idle trunk from the 
corresponding trunk group.
Dial the Trunk Group Access number 
and a trunk group number. Or press a 
G-CO button.
S-CO Line 
Access
Selects the desired trunk directly. Dial the S-CO Line Access number and 
the trunk number. Or press the S-CO 
button.
Type Assignable parameter
Loop-CO (L-CO)
No parameter (All assigned trunk groups 
through system programming are applied.)
Group-CO (G-CO) A trunk group is assigned.
Single-CO (S-CO) A specified trunk is assigned.
– The same trunk to the S-CO button and to a G-CO button
– The same trunk group to more than one G-CO button
– More than one L-CO button










