ATT DEFINITY Communications System Generic 3 Instructions Manual

							DCS Call Coverage
Issue  3   March 1996
3-617
3. The call is redirected to the first coverage point, which is on the remote 
system. Also, at this time the DCS distinctive ringing message is sent to 
the coverage point along with two messages conveying the caller’s name 
and the principal’s name.
4. The coverage point rings with internal ringing if the caller is on a DCS 
node, or with external ringing otherwise.
5. The covering user answers and receives the calling party’s name and 
principal’s name on the display if equipped.
Several other sc enarios can occur deviating from this normal situation, as 
follows:
n A call to the principal redirects to the remote coverage point, which is 
unavailable. The coverage p oint is considered unavailable in the following 
cases:
—  The coverage point is not a valid extension, QDN, or VDN.
—  The coverage point is busy with no hunting, forwarded, or has 
send all calls activate d, or activates send all calls after ringing.
—  The  coverage  point has no staffed agents or an invalid vector.
In the case of an unavailable coverage point, the local system learns of 
the availability status either through a time-out or from a message from the 
remote system. When the local system d etermines that the coverage point 
is unavailable, it tries the next coverage point. If the last coverage point is 
unavailable, the previous coverage point rings until answered or until the 
caller hangs up. If only one coverage point exists in the p ath and it is 
unavailable, the principal’s station rings until answered or until the caller 
hangs up.
n A call to the principal is forwarded and the forwarded-to extension is not 
available. In this case, the first coverage point in the principal’s path will 
be tried. Note that the coverage does not follow the forwarded-to 
extension’s coverage path.
n A call to the principal redirects to the remote coverage point, which 
answers. Subsequently, the principal goes off hook. In this case, the local 
system bridges the principal onto the call between the calling party and 
coverage point creating a conference among the three. The  principle 
receives the call on the same call appearance as the original call.
n A call to the principal redirects to the remote coverage point. While the 
remote coverage point is ringing, the principal answers the call. In this 
case the call is not cut through to the coverage point. Instead, ringing and 
ringback is removed from the coverage point and the call is c ut through to 
the principal. 
						

							Feature Descriptions
3-618Issue  3   March 1996 
Operation Under Error Conditions. The following table describes the operation 
of DCS Call Coverage under error conditions
In a ddition, call consult operates as follows when the DCS link is down: If user A 
calls user B but the call covers to user C, then if user C consults b ack to user B, 
user B receives the consult call on the next call appearance.
User Interface
The user interface for DCS Call Coverage consists of station alerting and terminal 
displays, including hospitality displays
Station Alerting. Station alerting operates the same as in Call Coverage, as 
follows:
nIf the call to the principal originated from a station within the DCS network, 
the coverage point receives internal ringing.
nIf the call to the p rincipal originated from a trunk, which means from a 
phone on  a switch outside the DCS network, the coverage point receives 
external ringing.
nIf the call to the p rincipal originated from an attendant within the DCS 
network, the coverage point receives external ringing.
Table 3-52. Error Conditions
Error Condition Action
DCS link not up .
or
DCS trunk is not available.
or
DCS Call Coverage feature is not 
activated on the remote system.The call is routed to the remote 
coverage point. If the call is 
answered, it is treated as Call 
Coverage Off Premises (also called 
Remote Call Coverage.) If the call is 
redirected at the remote coverage 
p oint b efore the DCS SRI expires, 
the remote point’s path will b e 
followed. If the call is not answered 
within the DCS SRI time-out p eriod, 
the next coverage point is tried with 
DCS Call Coverage from the local 
system.
All trunks to the remote system, DCS 
or otherwise, are busyThe next coverage point is tried with 
DCS Call Coverage from the local 
system. 
						

							DCS Call Coverage
Issue  3   March 1996
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Displays. Displays at the coverage point work the same as for Call Coverage 
with the exceptions caused by DCS. In general, the disp lay at the coverage point 
takes the form
a=   
For call coverage, this format is always true because the system has all the 
information it needs from the calling party, principal, and coverage point. Under 
most circumstances, DCS also has all the information it needs, providing it in 
messages. In some DCS circumstances, however, some information can be 
lacking or substituted with other information. Following are the formats for 
displays on the coverage point’s terminal under these special conditions
.
Figure 3-8. Display — DCS Trunks End-to-End
In the Figure 3-8, a call is made from the station on system A to the principal on 
system B and  covered by the station on system C. The tie trunks between A and 
S75, G1,
G3, S85,
or G2G3V4
System A System BP rinc ipa l
G3V4
C overage Poin t
System C DC S link DCS link
ISDN or non-
ISDN Tie trunk ISDN or non-
ISDN Tie trunk
Calling Party
Coverage Points Display
a=    
						

							Feature Descriptions
3-620Issue  3   March 1996 
B and B and C are DCS trunks transported over any kind of facility (ISDN or 
non-ISDN).
.
Figure 3-9. Display —  Non-DCS, Non-ISDN Trunk to DCS 
Trunk over Non-ISDN Trunk
In Figure 3-9, a call is made from the station on system A to the principal on 
system B and c overed b y the station on system C. The tie trunk b etween A and B 
is not a DCS trunk and is not an ISDN PR I trunk. The tie trunk  between B  and C is 
a non-ISDN PRI DCS trunk.
S75, G1,
or G3G3V3
System A System BPrincipal
G3V3
Coverage Point
System C DCS link non-ISDN trunk
non-ISDN trunk
Calling Party
Coverage Points Display
a=    
						

							DCS Call Coverage
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.
Figure 3-10. Display —  Non-DCS, Non-ISDN Trunk to DCS 
Trunk over ISDN Trunk
In Figure 3-10, a call is made from the station on system A to the principal on 
system B and c overed b y the station on system C. The tie trunk b etween A and B 
is not a DCS trunk and is not an ISDN PR I trunk. The tie trunk  between B  and C is 
a DCS ISDN PRI trunk.
S75, G1,
G3, S85
or G 2G3V4
S ystem A S ystem BPrincipal
G3V4
Coverage Point
System C DCS link N on-ISD N trunk
IS D N tru nk
C a llin g P a r ty
Coverage Points Display
a= < to>   
						

							Feature Descriptions
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.
Figure 3-11. Display —  Non-DCS ISDN Trunk to DCS ISDN 
Trunk
In Figure 3-11, a call is made from the station on system A to the principal on 
system B and c overed b y the station on system C. The tie trunk b etween A and B 
is not a DCS trunk but is an ISDN PRI trunk. The tie trunk between B and C is a 
DCS ISDN PRI trunk.
G1, G3,
S85 or G2G3V4
System A System BPrincipal
G3V4
Coverage Point
System C DCS link ISDN trunk
ISDN trunk
Calling Party
Coverage Points Display
a=    
						

							DCS Call Coverage
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.
Figure 3-12. Non-DCS ISDN Trunk to Non-ISDN DCS Trunk
In Figure 3-12, a call is made from the station on system A to the principal on 
system B and c overed b y the station on system C. The tie trunk b etween A and B 
is not a DCS trunk but is an ISDN PRI trunk. The tie trunk between B and C is a 
DCS trunk b ut not an ISDN PRI trunk.
If the calling p arty is a trunk on system A instead of a station, the displays are the 
same as above, substituting the calling trunk group’s names database for the 
station’s names d atabase. The exc eption to this is when system A is a System 85 
or G2, as follows:
G1, G3,
S85 or G2G3V4
System A System BPrincipal
G3V4
Coverage Point
System C DCS link ISDN trunk
non-ISDN trunk
Calling Party
Coverage Points Display
a=    
						

							Feature Descriptions
3-624Issue  3   March 1996 
.
Figure 3-13. Display — Call Initiated by a Trunk on System 85 
or G2
The display in this case depends on the administration on the G2. If the call is 
routed to trunk group AB via the internal dial plan (PROC 354 word 2), the G2 
sends a DCS name message for the calling trunk and the first display results. If 
the call is routed directly to a pattern without going through the internal dial plan, 
however, a name message is not sent, resulting in the second display. If trunk 
groups AB and BC are both ISDN PRI trunk g roups, however, the first display will 
result because the coverage point will display the contents of the ISDN PRI 
display information element.
The situations described above assume outgoing trunk group displays are 
turned off in the “Trunk Group” form, that the “Send Name” field is yes in the” 
ISDN Trunk Group” form, that the name message and display IEs have contents, 
which are taken from the station or trunk names databases, and that these 
messages are sent and received.
S85 or G2G3V4
System A System B
G3V4
Coverage Point
System C DCS link DCS link
non-ISDN trunk
any trunk
any trunk
Coverage Points Display
a=   
a=   
Principal
Calling Party
or 
						

							DCS Call Coverage
Issue  3   March 1996
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Hospitality Displays. If the hospitality feature is in use, the disp lay rules c an vary 
from those shown above depending on administration. The disp lays on terminals 
follow the same rules as above  except for one case  as  described in the following 
list.
nThe hospitality feature is enabled on the calling party’s system, the 
principals’ system, and on the coverage point’s system on page 2 of the 
“System Parameters Customer Options”  form.
nThe client room option is set to y on the “Class of Service” form for the 
calling party’s and the principal’s stations.
nThe “Display Client Re dir?” field is set to n on the “Coverage Point’s 
Station” form.
If the above conditions exist, the coverage point displays the following:
a=
In most hospitality a p plications, the extension is administered as the room 
number. If this is not the case, however, the administered room number can be 
displayed instead of the extension. This is accomplished by doing the following:
nSet the “Display Room Information?” field to y in the “Hospitality-Related 
System Parameters” form.
nEnter up to five characters in the “Room” field in the “Principal’s Station” 
form.
Interactions
DCS Call Coverage has the same interactions as Call Coverage plus interactions 
with the following features. For information on the Call Coverage interactions, see 
the Call Coverage feature description in this manual.
nCall Coverage Off Premises
DCS Call Coverage interacts with Call Coverage Off Premises as follows. 
If the coverage point is a non-UDP number in the remote call coverage 
table, Call Coverage Off Premises is a p plied to the call rather than DCS 
Call Coverage, even if a DCS link exists to the remote system.
nCoverage Answer Groups
DCS Call Coverage to Coverage Answer Groups on remote systems are 
not supported by DCS Call Coverage. Coverage answer groups cannot 
be a dministered on a system other than the principal’s system. 
						

							Feature Descriptions
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nCoverage Call Ba ck
DCS Call Coverage does not support Coverage Call Back from a remote 
node. This is because the c overage point’s system has no way of knowing 
whether the caller can respond to Leave Word Calling. For example, the 
coverage point’s system does not know whether the c alling party is a trunk 
or a station.
nDisplays
DCS Call Coverage interacts with displays as follows. Displays on the 
coverage point’s terminal can appear different than they do with Call 
Coverage in the following situations:
— When the call from the calling party to the principal or the 
redirected call to the coverage point travel over ISDN PRI trunk 
groups.
— When the calling party is on a System 85 or Generic 2.
— When the DCS name message is not received by the remote 
(coverage point’s) system.
For more d etail see the Displays section of this feature description.
nGoto Cover
Goto Cover is not supported over DCS and therefore is not supported with 
DCS Call Coverage.
nLeave Word Calling (LWC) Back to Principal
With DCS Call Coverage a covering user on a different node cannot press 
their LWC button to leave a message for the principal to call the covering 
user.
nQueuing
DCS Call Coverage interacts with queuing in the following way. If a call is 
queued to a coverage point, such as a queue to a hunt group or an ACD 
split, and the q ueue is not full, the call will stay in the queue without 
subsequent redirection until answered or until the caller hangs up.
Interworking
DCS Call Coverage contains considerations associated with interworking with 
ISDN PRI and with non-G3V4 systems. The interworking issues with ISDN PRI are 
actually issues related to DCS, not to DCS Call Coverage, but they do have 
consequences for how disp lays ap pear at the coverage point’s display terminal.