Instruction manual

Large business communications systems
5-20 Issue 9 May 2003
Free call list
For DEFINITY G2 and System 85, you can identify up to ten 3-digit telephone
numbers that can be called on otherwise-toll-restricted ports. This list allows toll
restricted phones to call emergency numbers, such as 911. This option can only
be used with TAC calls, not AAR/ARS calls.
NOTE:
This feature should be used only when CO trunks are obtained using TACs.
The preferred arrangement is always to use ARS/WCR.
AAR/ARS analysis
ARS routing allows calls to be routed based on the number dialed and the routing
plan in effect. The routing is normally to the lowest-cost facility. Different Time of
Day plans can be implemented to allow or prohibit calling at certain times.
NOTE:
Never route public network calls (leading digit = 0 or 1) via AAR analysis;
always cross over to ARS. (This happens automatically in G2 and
System 85 with ETN.)
Some long-distance area codes may start with the same digits as your local
exchanges. Be cautious when blocking access to those long-distance area codes,
so that access to required local exchanges is not simultaneously blocked. Since
COR/COS-to-COR/COS restrictions do not apply to AAR/ARS trunks, use FRLs
to limit the calling area [see ‘‘Facility restriction level’’ on page 5-19
for further
information].
ARS dial tone
For all switches, the dial tone after the ARS feature access code is optional and
can be eliminated to confuse hackers who listen for it. Conversely, its elimination
may also confuse authorized users who are accustomed to the second dial tone.
Station restrictions
If access to trunks via TACs is necessary for certain users to allow direct dial
access to specific facilities, use the appropriate restrictions. For DEFINITY G2
and System 85, assign miscellaneous trunk restriction groups (MTRGs) to all
trunk groups that allow dial access, then deny access to the MTRGs on the COS.
For Communication Manager, MultiVantage™ Software, DEFINITY ECS,
DEFINITY G1, G3, and System 75, if all trunk groups have their own unique COR,
then restrict the station CORs from accessing the trunk group CORs. For those
stations and all trunk-originated calls, always use ARS/WCR for outside calling.