ATT DEFINITY Communications System Generic 3 Instructions Manual

							Integrated Services  Digital  Network (ISDN) — Basic 
Rate Interface (BRI)
Issue  3   March 1996
3-797
Administered Connections
An Administered Connection is an end-to-end connection between two access 
endpoints or d ata endpoints that is automatically established by the system 
whenever the system is restarted or the Administered Connection is a dministered 
and the Administered Connection is due to be active. The attributes of these 
connections are user-defined and administered on the “Administered 
Connection” form via the G3-MT.
Once the ADM has been a dministered as one endpoint of an administered 
connection, the system waits for the scheduled time to set u p the connection. At 
the scheduled time, the system establishes the connection and maintains it for 
the specified length of time. Once the call is accepted, the set enters into the 
continuous mo de for the specified length of time. If the switch is reboote d during 
the continuous connection, the connection reinitiates the call setu p. At any time 
that the connection drops (for examp le, disconnected cabling), the switch 
re-initiates the call setup.
Call Request
The DEFI NI TY s yst em  Generic 3 call processing handles all various BRI Bearer 
data call requests that are presently defined. Some capabilities that are not 
supported by AT&T terminals may be provided by a non-AT&T terminal. The 
switch completes most call requests. For those c a pabilities the switch does not 
support, a proper cause value is sent back to the terminal.
Cause Value
BRI stations receive a cause or reason c o de that identifies why the call is being 
cleared. The BRI data modules convert certain cause values to text messages 
and d isplays them for the user.
Considerations
The system supports up to 60 simultaneous voice calls on a BRI since two 7507 
terminals (that support 30 call ap p earances/bridged appearances each) can be 
administered on a BRI port.
The following features are not provided to BRI users:
nSince the ISDN-BRI protocol requires that the Bearer Cap a bility must be 
specified at the time of sending the SETUP  message (and cannot be 
changed during the call), the following data functions are not provid e d to 
the BRI voice users:
— One b utton voice call setup transfer to d ata
— One b utton data call setup transfer to voice
— Preindication of a data call
— Voice call transfer to d ata and data call transfer to voic e 
						

							Feature Descriptions
3-798Issue  3   March 1996 
These functions require a change in the Bearer Cap a bility after the 
establishment of the call, which is currently not allowed by the BRI 
protocol.
nFeatures that use the switchhook and Recall button (for example, Call 
Waiting and Analog Conference/Transfer/Hold/Drop) are a p plicable to 
analog voice terminals only
The DEFI NI TY s yst em  s u pports BRI data endpoints that perform layer 2 
disconnect. BRI data endpoints that support layer 2 disconnect are administered 
as non-Management Information Message (MIM) supporting data only 
endpoints.
The DEFI NI TY s yst em  s u pports non-AT&T BRI voice and data terminals that 
perform enbloc sending using any one of the following formats:
nA  S ETUP   message with all the digits in the Keypad IE and a Sending 
Complete IE.
nA  S ETUP   message with all the digits in the Called Party Number IE and a 
Sending Complete IE.
nA  SETUP  message with all the digits in the Called Party Number IE and no 
Sending Complete IE.
If you are using a 7506D or 7507D to make calls that require a d ditional digits, 
you can place a comma in the dial sequence after you receive a second dial tone 
or after the call has been set up. The comma is used to separate the called 
number from subsequent information.
Interactions
The following features interact with the ISDN-BRI services:
nData Button
Besides the call appearance and feature function buttons, BRI voice/data 
terminals have a fixed, dedicated data button (button 7 on the 7505D and 
7506D voice terminals, and button 31 on the 7507D voice terminal) that is 
used for data call setup. In g eneral, feature function buttons such as Call 
Forwarding or Send All Calls buttons are always associated with voice 
features, and cannot be used in conjunction with the data button. For 
example, the user cannot activate call forwarding for the associated data 
endpoint by using the data button followed by the Call Forward ing button 
and the designated extension.
nInterworking
The same off-premises call types are permitted as for DCP, with the 
exception of voice to data and data to voice transfer. 
						

							Integrated Services  Digital  Network (ISDN) — Basic 
Rate Interface (BRI)
Issue  3   March 1996
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nModem Poolin g
The Modem Pooling feature provides the necessary protocol conversion 
between Mode 2 digital data endpoints and analog data facilities. A 
modem pool resource needs to be inserted by call processing during call 
setup for both call origination and c all answering. This resourc e translates 
data between DMI Mode 2 protocol used by BRI data endpoints and the 
modulated signal used by the modem.
nPre-Selection
When an ISDN-BRI station assigned with the “Select Last Used 
Appearance?” field of the “Station” form set to yes completes a transfer 
while off-hook using the handset, the user will be left hearing a dial tone on 
the last-used appearance, rather than the silence heard in the same 
situation by an user of other station types.
nVoice Terminal Display
BRI terminals take control of the disp lay. For example, when the user is in 
dialing state (BRI terminal is in the Overlap Sending state) any display 
information sent to the terminal from the switch is buffered until the state 
changes and is displayed when the state changes.
The 7506 BRI voice terminal, which has a 2-line 24-character display, 
splits a message when it recognizes a b lank closest to the 24th c haracter. 
This is left to the discretion of the terminal. As a result, the switch has no 
control over it.
nBusy Tone Forward Disconnect
BRI terminals require that the Busy Tone Forward Disconnect (BTFD) 
feature b e turned off. With BTFD of f,  an a g e nt (with Malicious Call Trace) is 
able to change states after a call. 
Administration
BRI Voice/Data
Administration of BRI voice terminals requires all the fields associated with the 
standard DCP station administration. Ad ditional fields are used to enter the 
following information:
nTEI information: If the BRI terminal supports a fixed TEI value, it has to be 
entered at the time of station administration. The allowed values are 0 
through 63. There are two fields: “Fixed TEI” and “TEI Value” . If the answer 
to the first field is yes, the second field shows u p where the TEI value is 
administered. The TEI value on the “Ad ministration”  form must match the 
value supported by the terminal.
nMIM support: This is an “ A dministrable”  field on the “BRI Station” form. If 
the answer to this field is ‘‘yes,’’ the following two fields need to be filled in: 
						

							Feature Descriptions
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1. Endpoint Initialization: If the BRI terminal supports endpoint 
initialization, the administrator has to enter the SPID value. The 
default value is the extension; however, the value can be changed 
at the time of a dministration. The SPID can be up to 10 digits, and 
uniquely identifies the terminal on the BRI. The SPID on the 
“ Administration”  form and the SPID programmed into the endpoint 
must be the same. (Refer to the terminal’s user manual in ord er to 
change the terminal’s SPID.) All SPIDs must be d ifferent for each 
endpoint on the same port. All SPIDs must be different from the 
service SPID, which is administered on the “System Maintenance” 
form.
2. MIM Maintenance / Management sup port: This is another BRI 
specific field that indicates if the terminal supports other 
maintenance and management messages.
For multipoint (passive bus) environment, the system administration checks the 
number of B-channels used for a port. Administration denies any attempt which 
might cause call blocking by restricting the numb er of en d points on a port.
NOTE:
Separate extensions numbers are used for voice and d ata calls to the same 
endpoint.
Any PC/ISDN Platform configuration (stand-alone, with handset/headset, or 
with voice terminal) should be administered with MIM support set to ‘‘no’’. 
Other administrable features depend on the PC software application (if the 
application supports data transmission, the ‘‘Data Module’’ field must be 
set to ‘‘yes’’).
BRI Data
The 7500 Data Module is a dministered through the “Data Module Ad ministration”  
form. The ADM is a dministered through the “Station Ad ministration”  form, using 
the data module administration p a ge. In add ition to the fields used by the DCP 
endpoints, the following new fields are used for BRI data module administration:
nDefault Duplex: Full/Half (default Full)
nDefault Mo de: Synchronous/Asynchronous (default Asynchronous)
nDefault Speed: 1200, 2400, 4800, 9600, 19200, 56000, and 64000 (default 
1200)
(In synchronous mode, the speed of the 7500 data module may be set to 
56,000 or 64,000 bps.)
nDefault Data Ap p lication: mode 0, mode 1, mode 2 sync, mode 2 async, 
and mode 3/2 adaptable
Default Duplex, Default Mode, and Default Speed values are used for initializing 
data module d efault attributes. The defaults are required for modem pooling 
conversion resource insertion when the en d point does not support MIM query  
						

							Integrated Services  Digital  Network (ISDN) — Basic 
Rate Interface (BRI)
Issue  3   March 1996
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capability. If you are using supported end p oints (7500 and ADM), you should not 
change the d efault values. Changing the default values with the MIM 
Maintenance/Management support o ption as ‘‘y’’ has no effect on modem 
pooling. These endpoints support the MIM query capability, which enables the 
switch to query the endpoint when a call arrives.
Default Data Ap p lication specifies the default data protocol to b e used for 
originating data calls if mode is not sp ecified with the calling parameters. This 
mode is also use d for Administered Connections and for terminating trunk calls 
that do not have bearer capability specified.
Data mo dules that sup p ort two simultaneous data calls should be administered 
as a 7500 and the MIM Maintenance/Management support option should be set 
to ‘‘n.’’
NOTE:
Two simultaneous data calls to a single endpoint use the same extension 
numb er.
Hardware Requirements
BRI services require the following hardware:
nThe TN778 Packet Control circuit pack. This circuit pack provides the 
interface to the LAN (packet) bus on G3i (but not G3r) for establishing the 
signaling connectivity.
nThe TN556 BRI p ort circuit pack, which is the Basic Rate Line circuit pack. 
Each BRI p ort board  c an support 12 line interfaces, each operating at 192 
kbps.
nA TN2198 two-wire BRI port circuit pack can be used in place of the 
TN556. In this case an NT1 is also required.
nISDN-BRI Typ e B and Type D Terminal Management S/T interface 
terminals.
nThe AT&T ISDN 7505, 7506, 7507, 8503T, 8510, and 8520 voice terminals.
nThe 7500 Data Module and the ADM. The ADM is supported by the AT&T 
ISDN 7505, 7506, and 7507 voice terminals with firmware version FP2.0 or 
later.
nThe PC/ISDN Interface card used in conjunction with a standard PC and 
one to four voice terminals.  See the 
PC/ISDN Platform Installation and 
Reference 
manual, 555-016-102, for a d ditional information. Also see the 
PC Interface feature d esc rib e d in this book. 
						

							Feature Descriptions
3-802Issue  3   March 1996 
Integrated Services Digital Network
(ISDN) — Primary Rate Interface
Feature Availability
ISDN-PRI is an optional feature that can be purchased with any Generic 3 
releases except G3vs/G3s ABP. 
Description
Allows connection of the system to an Integrated Services Digital Network (ISDN) 
by using a standard ISDN frame format called the Primary Rate Interface (PRI). 
The ISDN gives the system users access to a variety of public and private 
network services and facilities. The ISDN-PRI standard consists of layers 1, 2, 
and 3 of the Open System Interconnect (OSI) model. In ISDN-PRI, the 
transmission standard for layer 1 (the physical layer), is either DS1 (T1) or CEPT1 
(E1).
The DS1 (T1) is a digital transmission standard that in North America carries 
traffic at the digital signal level-1 (DS1) rate of 1.544 Mbps. T1 facilities are also 
used in Japan and some Middle-Eastern countries. It consists of a 1.536 Mb ps 
signal multiplexed with an 8 kbps framing channel. The 1.536 Mb ps signal is 
divided into 24 channels (DS0s) of 64 kbps each, numb ered 1 - 24. The ‘‘D’’ 
(data) channel multiplexes signaling messages for the ‘‘B’’ (bearer) channels 
carrying voice or data. When a D-channel is present, it o c cupies Channel 24.
The CEPT1 (E1) is a d igital transmission standard that  carries traffic at a rate of 
2.048 Mbps. It is used in Europe and elsewhere. The E1 facility is divided into 32 
channels (DS0s) of 64 kpbs information numb ered 0-31. Channel 0 is reserved 
for framing and synchronization information. When  a D-channel is present, it 
occupies channel 16.
The DEFI NI TY s yst em  of f ers several administrable protocols, each of which 
provides a different set of services that ISDN-PRI allows. For country 1 (U.S.A.), 
users can administer either the AT&T Switched Network or National ISDN-2. 
These protocols are discussed in detail later in this section. For other countries, 
the DEFINITY system provides a Global ISDN-PRI. This includes any combination 
of services, including (but not limited to) Basic Call, DDI, Disp lay, and QSIG. The 
services available with Global ISDN-PRI are country-dependent. (Please refer to 
the QSIG  Global  Networking  feature.
ISDN-PRI signaling in the system is supported by the TN767 (for 24 channels) or 
the TN464C or later version (for 24 or 32 channels) DS1/E1 Trunk circuit packs, 
coupled with (for all releases except G3r) the TN765 Processor Interface circuit 
pack. The  D-channel (signaling channel) is switched through the TN765 circuit 
pack. 
						

							Integrated Services  Digital  Network (ISDN) — Primary 
Rate Interface
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NOTE:
For G3r, the D-channel information can only use the TN464C (or later 
version) circuit pack; TN767 can be used for NFAS interfaces carrying only 
B-channels, but not for ISDN signaling information (D-channel).
With the ISDN-PRI, the system can interface with a wide range of other products 
including network switches, PBXs, and host computers. These products include 
the following:
nPublic Network switches (for example, 4ESS, 5ESS, Northern Telecom 
DMS250, etc.)
nDEFI NI TY Com munications System Generic 2 and System 85 R2V4.
nDEFI NI TY Com munications System Generic 1
nDEFI NI TY Com munications System Generic 3
nSome of the other products that adhere to the ISDN-PRI signaling 
protocol.
As an example of how the ISDN-PRI is used in private and public network 
configurations, see Figure 3-20 and Figure 3-21. As seen in these figures, the 
ISDN-PRI c a n b e u se d to interface a PBX to a Public Switched Network, a PBX to 
a Host Computer, or a PBX to another PBX.
Figure 3-20. ISDN-PRI Private Network Configuration
ISDN-PRI DEFINITY
COMMUNICATIONS
SYSTEM
HOST
COMPUTERDEFINITY
COMMUNICATIONS
SYSTEM
DEFINITY
COMMUNICATIONS
SYSTEM 
						

							Feature Descriptions
3-804Issue  3   March 1996 
Figure 3-21. ISDN-PRI Public Network Configuration
AT&T Switched Network Protocol
The AT&T Switched Network Protocol is an ISND-PRI protocol that uses 4ESS 
implementation. The DEFI NIT Y syst em  ISDN-PRI implementation is consistent 
with the ITU-T Recommendation Q.931 and Q.921 for ISDN signaling. The AT&T 
Switc h ed  Network provides system users with the following services:
nAccess to AT&T Switched Network Services (for example, SDN, MEGA, 
etc.)
nCall Identification Display
— Calling Party Num ber (CPN)
— Billing Number (BN)
— Calling and Connected Number Display
— Calling and Connected Party Name Display
nCPN/BN to Host Call Identification
nPrivate Network Services
nWideband (NxDSO, H0, H11, H12) (both private and public networks)
nCall-by-Call Service Selection
These services are discussed in detail in the following subsections.
ISDN-PRI DEFINITY
COMMUNICATIONS
SYSTEM
HOST
COMPUTERPUBLIC
SWITCHED
NETWORK
(4 ESS)DEFINITY
COMMUNICATIONS
SYSTEM
DEFINITY
COMMUNICATIONS
SYSTEM ISDN-PRI 
						

							Integrated Services  Digital  Network (ISDN) — Primary 
Rate Interface
Issue  3   March 1996
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Access to AT&T Switched Network Services
ISDN-PRI pro vides access to AT&T Switched Network Services such as SDN 
(Software Defined  Network), SDDN (Software Defined Data Network), 
MEGACOM, etc. An ISDN-PRI trunk group may be dedicated to a particular 
feature. Alternately, an ISDN-PRI call-b y-call trunk group may provide access to 
several features. For a description of the ASN services accessible via ISDN-PRI 
(either via dedicated or call-by-call trunk groups) see the Call-by-Call Service 
Selection feature description elsewhere in this document.
Call Identification Display
ISDN-PRI Call Identification Display provides a transparent name/number d isplay 
for all display-equipped voice terminals within an ISDN-PRI network. The feature 
is transparent in that the same information is provided at all ISDN-PRI facilities. 
Voice terminals using this feature should be digital voice terminals with a 
%40-character alphanumeric display. The Merlin hybrid sets with 32-character 
displays (7315H and 7317H) also support this feature.
ISDN-PRI Display Information is provid e d in addition to the normal Voice 
Terminal Display and Attendant Display features, when the network supports 
end-to-end ISDN-PRI connectivity. When both ISDN-PRI and DCS d isplay 
information, or DCS display information only, are received, the switch displays 
the DCS  display information in the DCS format. If ISDN disp lay information is 
received, and no DCS display information is received, then the ISDN display 
information is displayed in the ISDN formats.
Two types of identification numb ers are provided with the ISDN-PR I. These 
identification numbers may be used in the various typ es of displays used with the 
ISDN-PRI. The two types of identification numbers are as follows:
nCalling Party Num ber (CPN): A 0 to 15 d igit DDD number ass o ciated with 
a specific station.  When a system user makes a call that uses the ISDN, 
that user’s CPN is provided by the system for the ISDN. The “CPN Prefix” 
form is administered to create a 0-15 digit CPN from a local station 
number.
nBilling Number (BN): The calling party’s billing number that is provided to 
an inter-exc hange network via Equal Ac cess or Centralized Automatic 
Message A c counting (CAMA). This number is stored at either a local or 
network switch. If a customer is connected directly to the AT&T network, 
the BN  is the customer’s billing numb er stored in that network. If the CPN 
is not provided on an incoming ISDN-PRI c a ll, the system uses the BN for 
the station identification numb er.
The following types of display information are provided with the ISDN-PRI.
nCalling Party’s Number
The calling party’s number is shown on the called p arty’s display. On calls 
generated from a DEFINITY system, the calling party’s number is a 0- to 
15-digit DDD number. This number is provided only if the outgoing 
ISDN-PRI trunk group is administered to send the CPN and if the “ CPN  
						

							Feature Descriptions
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Prefix”  form is a dministered to c reate a CPN. For G3vs/G3sV1, G3iV1, and 
G3rV1, the Calling Party number, if sent, is always 10 digits long. On calls 
incoming to a system, the network may provide either the CPN or BN as 
the calling party’s numb er.  Exc ept for G3i-Global, dashes are inserted in 
the displayed number between the area code (if shown), the office code, 
and the local number. Extension numbers and 12-digit international 
numbers are shown without dashes. For G3V2 and later releases, dashes 
are only used for 7-digit and 10-digit numbers when the ‘‘North American 
Area Code’’ field is administered on the ‘‘Dial Plan” form.’
nCalling Party’s Name
The calling party’s name is shown on the called party’s display. On calls 
generated from a DEFINITY system, the calling party’s name is provided if 
the ISDN-PRI trunk group is administered to send the name to the network. 
On calls incoming to a DEFINITY system, the (p ublic or private) network 
may provide the calling party’s name. If the calling party’s name is not 
available, the called party’s display shows ‘‘CALL FROM’’ instead, 
followed by the calling party’s number (if available).
nConnected Party’s Number
The connected party’s number is shown on the calling party’s display. On 
calls generated from a DEFINITY system, the called party’s number is 
shown on the calling party’s display as the calling party dials the number. 
If the (public or private) ISDN network provides the connected party’s 
number, the calling party’s display is u pdated to show the connected 
party’s number. The format of the connected party’s number is the same 
as that of the calling party’s number described previously on calls 
incoming to a DEFI NIT Y syst em . The 0-15 d i git number of the p arty who 
answers the call is provided to the ISDN network only if the incoming 
ISDN-PRI trunk group is administered to send the CPN to the network and 
the “ CPN Prefix”  form is a dministered to create a CPN.
NOTE:
The connected party may or may not be the party actually called.
For G3vs/G3sv1, G3iV1, and G3rV1, the connected party number, if sent, 
is always 10 digits long.
nConnected Party’s Name
The connected party’s name is shown on the calling party’s display. On 
calls generated from a DEFINITY system, the (public or private) ISDN 
network may provide the connected party’s name to the DEFINITY  syst em,  
when the call is answered. If the connected  party’s name is not available, 
the calling party’s disp lay shows 
ANSWERED BY, followed by the 
connected party’s numb er (if available).