Toshiba DK40I 用户手册

There are two variables that can be programmed for each trunk group to ensure optimum call 
utilization. These are the minimum and maximum values.

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The minimum (min.) value is defined as the minimum number of B-channels in reserve that 
are necessary to ensure that a given trunk group can adequately service calls. The default value 
is zero. 

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The maximum (max.) value is the maximum number of B-channels that are necessary to 
ensure that a given trunk group can adequately service calls during a peak period. The default 
value is 23.  

The min and max values must be determined by you based on the traffic volume and environment. 
Here are some guidelines:

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The total number of lines assigned to all trunk groups as minimums should not exceed the 
number of B-channels in the channel group.  For example, if there are 23 B-channels in the 
channel group, the total sum value programmed as minimum in all trunk groups should not 
exceed 23.

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The maximum value typically never exceeds the total of the subscribed B-channels for the 
channel group. The programmed maximum value is typically used to limit the total number of 
shared lines available to a given trunk group.

This example shows how to determine the maximum number available to a trunk group. 

. Add the min. values from the other trunk groups, then subtract that sum from 

the number of B channels in the channel group. The remainder is the total number of lines 
available for that trunk group. This is outlined in steps 1 and 2 below.

Maximum trunk group values are set in Program *67-4. Minimum trunk group values (reserved) 

are set in Program *67-3.

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1. Determine the total number of lines 

available to Trunk Group 1.

2. Subtract from other Trunk Groups’ 

min. values from the number of 
B-channels in that Channel Group.

Trunk Group 2 Min.

Trunk Group 3 Min.

Min. Value for Trunk Groups 2 & 3

B-channels in Channel Group 1

Min. Value for Trunk Groups 2 & 3

Lines available to Trunk Group 1

(8 reserved + 7 shared)

Even through the max. value is 
set for 23 channels, only 15 
channels are available for 
Trunk Group 1.