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Call-By-Call Overview
Strata DK Programming 5/00 7-11
Call-by-Call Line Sharing
The Call-by-Call feature enables you to reserve (dedicate) a specific number of channels for a
specific trunk group, such as DID or Tie lines, and to enable a specific number of channels (lines)
to be shared. Shared lines are automatically pooled when they are not in use and can be used by
other trunk groups within the channel group to service calls on a Call-by-Call basis. The Reserved
quantity of lines for one trunk group cannot be used by other trunk groups and are dedicated to the
assigned trunk group service.
Example 1
In Call-by-Call, each trunk group has a number of channels reserved as “minimum” and a number
of channels available to be shared. Shared channels are available on a Call-by-Call basis.
For example, in Figure 7-2, 11 channels (2 + 5 + 4 = 11) are programmed as the minimum number
of reserved channels in Trunk Groups 1, 2 and 3. To determine the number of channels available to
be shared, subtract the minimum channels from the 23 total channels (23 - 11 = 12).
1
2
3
4
23
2 programmed as minimum
for 800 numbers
23 total channels
-11 minimum channels
12 shared channels
The 12 shared channels
are available to all three
trunk groups on a
Call-by-Call basis, first
come, first served.
Trunk Group 1
5 programmed as minimum for DIDs
Trunk Group 2
4 programmed as minimum
for Tie line calls
4915
Trunk Group 3
B-Channels
ISDN Channel Group 1
has 23 B-channels available
for Trunk Groups 1, 2 and 3.
ISDN
Channel Group 1
Minimum
You can reserve B-channels for trunk
groups by programming them as
“minimum.” Trunk Group 1 above has
2 minimum, Trunk Group 2 has 5,
and Trunk Group 3 has 4. There are a
total of 11 (2 + 5 + 4) minimum
channels.
Shared
The number of shared channels
available for a particular trunk
group varies dynamically
according to the usage by other
trunk groups.
Figure 7-2 Example 1 – Call-by-Call and Min/Max Control