6-8 Server Cards
Model No.
Running Head
Introduction ACS-PRI/BRI Card
6.1.4 Call Routing
The system can be simultaneously connected to several network and user side ACS-PRI/ BRI
facilities and to a user’s data terminal equipment (DTE) such as a video codec or a LAN router .
The DTE is typically connected through one or more of the system’s HSU cards.

6.1.4.1 Calls Originating from an HSU Port

Any call originating from an HSU port must be associated with a call profile (see Call Profi les
section). The call profile specifies wh ich D channel is to carry the call. The sy stem will always
route an outgoing HSU call to B channels controlled by the D channel specified in the call
profile. If no B channels are available, the call will not be placed.

6.1.4.2 Calls Destined to an HSU Port

Each HSU port in the system that is available to receive incoming calls must be assigned a
unique primary phone number that allows the system to route an incoming call to it (see the
Dial screen in the HSU section). Optionally, a hunt group phone number (which need not be
unique) can also be assigned to the same HSU port.
When an incoming call is received by the system, it first scans all of th e pr imary HSU phone
numbers to attempt a match. If a match occurs, the call is routed to that HSU port. If no match
is found, the system then searches the list of hunt group number s to find a match. The ca ll will
be routed to the first HSU port with a matching hunt group phone number.
If a match is still not found, the system begins searching the D channel rout ing tables (s ee next
section). If no match is found after all sear ches are finished, the system rejects the i nc oming
call.

6.1.4.3 Calls Originating from a D Channel

All calls originating from a D channel are considered incoming call s to the syst em because the
system is first made aware of the call whe n an incoming call message is received on t he
originating D channel.
As described above, the system first tries to route any incoming call from a D channel to an
HSU port. If it cannot match the called number to an HSU port primary number or hunt group
number, the system begins looking in the D channel routing tables (see Assignment of Call
Routing Information later in this chapter) . It will route the call to the first D cha nnel it matches.
If no D channel routing information matches, the call is rejected. As are used as "wildcards"
that will allow any number in its place to match. It is recommended that one carrier D
channel be assigned the default routing code of “xxx-xxx-xxxx” so that ther e will al ways
be a match.