ATT DEFINITY Communications System Generic 3 Basic Call Management System Instructions Manual

							Glossary
Issue  4  September 1995GL-11 
data link
The configuration of physi cal facilities enabling end terminals to communicate directly with each 
other.
data module
An interconnection device between a basi c rate interface (BRI) or digital communications proto-
col (DCP) interfac e of the switch and data terminal equipment (DTE) or data communications 
equipment (DCE).
data path
The end-to-end  connection used for a data-communications link. A data path is the combination 
of all the elements of an interprocessor communication in a distributed communications system 
(DCS).
data port
A point of access to a computer that uses trunks or lines for transmitting or receiving  data.
data rate
See bit rate.
data service unit (DSU)
A device designed to transmit digital data on transmission facilities.
data terminal
An input/output (I/O) device that has either switched or direct access to a host computer or to an 
applications processor (AP).
data terminal equipment (DTE)
Equipment consisting of the end p oints in a connection over a data circuit. For example, in a con-
nection between a data terminal and a host, the terminal, the host, and their asso ciated modems 
or data modules make up the DTE. DTE usually consists of the following functional units: control 
logic, buffer store, and one or more input or output devices or computers. DTE can contain error 
control, syn chronization, and telephone-identification capabilities.
D-channel backup
D-channel backup is used with Non-Facility Asso ciated Signaling (NFAS). With D-channel 
backup, a primary D-channel provides signaling for an NFAS D-channel group (two or more PRIs 
fac ilities). A se cond (redundant) %D-channel, located on a separate PRI facility of the NFAS 
D-channel group is designated as backup for the D-channel. The failure of the primary D-channel 
causes an automatic transfer of call-control signaling to the bac kup D-channel. When this hap-
pens, the backup becomes the primary D-channel, and when the previous primary is returned to 
servi ce it becomes the backup D-channel.
delay-dial trunk
A trunk that allows dialing directly into a communications system (em that is, the digits are 
received as they are dialed.
denying a request
Denying a Request is the same as sending a negative acknowledgement (NAK), and is done by 
sending  an Facility Information Element (FIE) with a 
return error c omp onent (a cause value is also 
provided). It should not be confused with the ‘‘denial’’ event report which applies to calls.
designated voice terminal
The specific voic e terminal to which calls, originally directed to a certain extension number, are 
redirected. Commonly used to mean the ‘‘forwarded-to’’ terminal when Call Forwarding All Calls is 
active. 
						

							Glossary
GL-12Issue  4  September 1995 
dial-repeating tie trunk
A tie trunk that transmits called-party addressing information between two communications sys-
tems.
digit conversion
A process used to convert specific dialed numbers into other dialed numbers.
digital communications protocol (DCP)
An AT&T proprietary protocol used to transmit both d i gitize d voice and  digitized data over the 
same communications link. A DCP link is made up of two 64 ~k b ps information (I-) channels and  
one 8-kbps signaling (S-) channel.
digital data endpoints
In G3iV2, digital data endpoints include devi ces such as the 510D terminal or the 515-type busi-
ness communications terminal (BCT).
digital multiplexed interface (DMI)
An interface that provides connectivity between a communications system and a host computer 
or between two communications systems using  digital signal level-1 (DS1) 24th-channel signal-
ing. DMI provides 23 64 ~kbps data channels and 1 common signaling channel over a 
twisted-pair connection. DMI is offered through two capabilities: bit-oriented signaling (DMI-BOS) 
and message-oriented signaling (DMI-MOS).
digital signal level 0 (DS0)
A single 64 kbps voic e channel. A DS0 is a single 64 kb p s  channel in a T1 or E1 facility and con-
sists of eight bits in a T1 or E1 frame every 125 micro-seconds.
digital terminal data module (DTDM)
An integrated or adjunct data module that shares with a digital telephone the same physi cal port 
for connection to a communications system. The function of a DTDM is similar to that of a proc es-
sor data module (PDM) and modular processor data module (MPDM) in that it converts RS232C 
signals to DCP signals.
digital-to-analog converter
A device that converts data in digital form to the corresponding analog signals. See also ana-
log-to-digital converter.
digital transmission
A mode of transmission in which the information to  be transmitted is first converted to  digital form 
and then transmitted as a serial stream of pulses.
digital trunk
A circuit in that carries digital voice and/or digital data in a telecommunications channel.
dial-repeating trunks
A PBX tie trunk that is capable of handling PBX station si gnaling information without attendant 
assistance.
direct agent
A switch feature ac c esse d only via Adjunct Switch Applications Interface (ASAI) whi ch allows a 
call to be placed in a split queue but routed  only to a sp e cific  agent in that split. This allows a call 
to receive normal ACD call treatment (for example, announcements) and to be measured as an 
ACD call while ensuring that a particular agent answers.
Direct Extension Selection (DXS)
A feature on an attendant console that allows an attendant direct access to voice terminals by 
pressing a group select button and a DXS button. 
						

							Glossary
Issue  4  September 1995GL-13 
Direct Inward Dialing (DID)
A feature that allows an incoming call from the public network (not FX or WATS)  t o  reach a spe-
cific telephone without attendant assistance. DID calls to DID-restricted telephone lines are 
routed to an attendant or recorded announcement, depending on the option selected.
direct inward dialing (DID) trunk
An incoming trunk used for dialing  d irectly from the public network into a c ommunications system 
without help from the attendant.
disk drive
An electromechanical device that stores data on and retrieves data from one or more disks.
distributed communications system (DCS)
A network configuration linking  two or more communications systems in such a way that selected 
features appear to operate as if the network were one system.
domain
Available domains are VDNs, ACD splits, and stations. The VDN domain is only used for 
active-notification asso ciations, the station domain is only used for the domain-control associa-
tions. The ACD-split domain is for active-notification associations and  domain-control associa-
tions.
domain-control association
A 
Third Party Domain Control Request capability initiates a unique ‘‘CRV/link number’’ combina-
tion, which is referred to as a domain-control association.
domain-controlled split
A split for whic h 
Third Party Domain Control request has been accepted. A domain-controlled 
split provides an event report for logout.
domain-controlled station
A station for which a 
Third_Party_Domain_Control request has been accepted. A domain-con-
trolled station provides event reports for calls that are alerting, connected, or held at the station.
domain-controlled station on a call
A station active on a call which provides event reports over one or two domain-control asso cia-
tions.
duplicated common control
Two processors ensuring continuous operation of a communi cations system. While one processor 
is on-line, the other functions as a backup. The backup processor goes on-line periodically or 
when a problem  condition occurs.
duplication
The use of redundant components to improve availability. When a  duplicated subsystem fails, its 
backup redundant system automatically takes over.
duplication option
A system option that duplicates the following :
nControl carrier, which contains the switch processing element (SPE)
nExpansion interface (EI) circuit packs in carriers
nFiber-optic cabling between port networks (PNs)
nCenter-stage switch (CSS) in a CSS-connected system 
						

							Glossary
GL-14Issue  4  September 1995 
E
E1
A digital transmission standard that carries traffic at the rate of 2.048 Mbps.
The E1 facility is  divid e d into 32 channels (DS0s) of 64 kb p s information numbered from 0 ~to 31. 
Channel 0 is reserved for framing and synchronization information. When a D-channel is  present, 
it occ u pies channel 16.
ear and mouth (E&M) signaling
Trunk supervisory signaling, used between two communications systems, whereby signaling  
information is transferred through two-state voltage conditions (on the E and M leads) for analog  
applications and through a single bit for digital  applications.
electronic tandem network (ETN)
A tandem tie trunk network that has automatic call routing   capabilities based on the number 
d ialed and the most p referred route available at the time the call is placed. Each switch in the net-
work is assigned a unique private network office c o de (RNX), and each voice terminal is assigned 
a unique extension number.
Electronics Industries Association (EIA)
A trade association of the electronic s industry that establishes electrical and functional standards.
emergency transfer
If a major system failure oc curs, the automatic transfer within a communications system of a pre-
d efined set of central offic e (CO) lines to a group of answering telephones with at least one tele-
phone capable of making outgoing calls. The system operates in this mode until the failure is 
repaired and the system automatically returns to normal operation. Also called ‘‘power-failure 
transfer.’’
end-to-end signaling
The transmission of touch-tone signals generated by dialing from a voice terminal user to remote 
computer equipment. A connection must first be established over an outgoing trunk from the call-
ing party to the comp uter equipment. Then  additional digits can be dialed to transmit information 
to be processed by the computer equipment.
enhanced private-switched communications service (EPSCS)
An analog private telecommunications network b ased  on the No. 5 Crossbar and 1A ESS that pro-
vides ad vanced voice and data telecommunications services to companies with many locations.
Erlang
A unit of traffic intensity, or load, used to express the amount of traffic it takes to keep one facility 
b usy for one hour. One Erlang is equal to 36 CCS. See also Hundred Call Seconds.
expansion archangel (EAA)
A network-control mi croprocessor located on an expansion interface (EI) port circuit pack in an 
expansion port network (EPN). The EA provides an interface between the EPN a n d its c ontrolling 
switch processing element (SPE).
expansion-archangel link (EAL)
A link-ac c ess function on the D-channel (LAPD) log i cal link that exists between a switch process-
ing element (SPE) and an ex pansion archangel (EA). The EAL carries control messages from the 
SPE to the EA and to port circuit packs in an expansion port network (EPN).
expansion control cabinet
See  expansion control carrier. 
						

							Glossary
Issue  4  September 1995GL-15 
expansion control carrier
A carrier in a multicarrier cabinet that contains extra port circuit packs and a maintenance inter-
fac e. Also called ‘‘ex pansion control cabinet’’ in a single-carrier cabinet.
expansion interface (EI)
A port circuit pack in a port network (PN) that provides the interface between a PN’s time-division 
multiplex (TDM) bus and packet bus, and a fiber-optic link. The EI carries circuit-switched data, 
packet-switched data, network control, timing control, and DS1 control. In ad d ition, an EI in an 
expansion port network (EPN) c ommuni c ates with the master maintenance circuit p a ck to p rovide 
the EPN’s environmental and alarm status to the switch processing element (SPE).
expansion port network (EPN)
A p ort network (PN) that is c onnected  to the TDM bus and p ac ket bus of a processor port network 
(PPN). Control is achieved by indirect connection of the EPN to the PPN via a p ort-network link 
(PNL). See also port network.
extension-in
Extension-In (ExtIn) is the work state agents go into when they answer (rec eive) a non-ACD c all. If 
the agent is in Manual-In or Auto-In and receives an extension-in call, it is recorded by CMS as an 
AUX-In call.
extension-out
Extension-Out (ExtOut) is the work state agents go into when they place (originate) a non-ACD 
call. If the agent is in Manual-In or Auto-In and  places an extension-out c all, it is recorded by CMS 
as an AUX-Out call.
external measurements
Refers to those ACD measurements that are made by the External CMS adjunct.
extension number
A 1- to 5-digit number by which calls are routed through a communications system or, with a Uni-
form Dial Plan (UDP) or main-satellite dialing plan, through a private network. Extension numbers 
are primarily used for telephones and data terminals but can also be used with specific features.
external call
A connection between a communications system user and a party on the public network or on 
another communications system in a private network.
F
facility
A general term used for a telecommunications transmission pathway and associated equipment.
facility associated signaling (FAS)
Signaling in which a D-channel carries the si gnaling only for those c hannels on the same physical 
interface.
feature
A specifically defined function or service provided by the system.
feature button
A labeled  button on a telephone or attendant console used to access a specific feature. 
						

							Glossary
GL-16Issue  4  September 1995 
fiber optics
A technology using materials that transmit ultrawideband electromagnetic light-frequency ranges 
for high-capacity carrier systems.
fixed
Fixed is a trunk allocation term. In the fixed allocation scheme, the time slots necessary to su pport 
a wideband  call are contiguous, and the first time slot is constrained to certain starting points.
flexible
Flexible is a trunk allo cation term. The flexible allocation scheme allows the time slots of a wide-
b and call to occ u py noncontiguous positions within a single T1 or E1 facility.
floating
Floating is a trunk allocation term. In the floating allocation scheme, the time slots necessary to 
su p port a wideband call are contiguous, but the position of the first time slot is not fixed .
foreign exchange (FX)
A central office (CO) other than the one providing local access to the public telephone network.
foreign exchange trunk
A telecommunications channel that directly connects the system to a central office (CO) other 
than its local CO.
foreign numbering-plan area code (FNPAC)
An area code other than the local area code. The FNPAC must be dialed to call outsi de the local 
geographical area.
G
generalized route selection (GRS)
An enhancement to Automatic Alternate Routing/Automatic Route Selection (AAR/ARS) that per-
forms routing   based on call attributes, suc h as Bearer Capability Classes (BCCs), in addition to 
the address and facilities restriction level (FRL), thus facilitating a Uniform Dial Plan (UDP) that is 
independent of the type of call being  pla ced.
glare
The simultaneous seizure of a two-way trunk by two communications systems, resulting in a 
standoff.
grade of service
The number of call attempts that fail to receive service immediately. Grade of servic e is also 
expressed as the quantity of all calls that are blocked or delayed.
ground-start trunk
A trunk on which, for outgoing calls, the system transmits a request for services to a distant 
switching system by grounding the trunk ring lead. To receive the digits of the called number, that 
system grounds the trunk tip lead. When the system detects this ground, the digits are sent.
H
handshaking logic
A format used to initiate a data connection between two data module devic es. 
						

							Glossary
Issue  4  September 1995GL-17 
H0
An ISDN information transfer rate for 384 kb ps data defined by CCITT and ANSI standards.
H11
An ISDN information transfer rate for 1536 kbps data defined by CCITT and ANSI standards.
H12
An ISDN information transfer rate for 1920 kbps data defined by CCITT and ANSI standards.
Hertz (Hz)
A unit of frequency equal to one cycle per second.
high reliability system
A system having the following: two control carriers, duplic ate expansion interface (EI) circuit 
p a c ks in the PPN (in G3r with CSS), an d   duplicate switch node clock circuit packs in the switch 
node (SN) carriers. See also duplicated common control, duplication, duplication option, and 
critical reliability system.
holding time
The total length of time in minutes and seconds that a facility is used  during a call.
home numbering-plan area code
The local area code. The area code does not have to be dialed to call numbers within the local 
geographical area.
hop
Nondirect communic ation b etween two switch c ommunic ations interfaces (SCIs) whereby the SCI 
message passes automatically without intermediate processing through one or more intermediate 
SC I s .
host computer
A computer, connected to a network, that processes data from  data-entry devices.
hunt group
A group of extensions that are assigned the Station Hunting feature so that a call to a busy exten-
sion will reroute to an idle extension in the group.
I
immediate-start tie trunk
A trunk on which, after making a connection with a distant switching system for an outgoing call, 
the system waits a nominal 65 ms before sending  the d igits of the called number. This allows time 
for the distant system to prepare to receive digits. On an incoming call, the system has less than 
65 ms to prepare to receive the digits.
information exchange
The exchange of data between users of two d ifferent systems, su ch as the switch and a host c om-
puter, over a local area network (LAN).
information systems network (ISN)
A wide area network (WAN) and local area network (LAN) with an open architecture combining 
host comp uters, minicomputers, word processors, storage devic es, PCs, high-speed printers, 
and nonintelligent terminals into a single packet-switching system.
inside call
A call placed from one telephone to another within the local communications system. 
						

							Glossary
GL-18Issue  4  September 1995 
Integrated Services Digital Network (ISDN)
A public or private network that provides end-to-end digital communications for all servi ces to 
which users have access by a limited set of standard multipurpose user-network interfaces 
d efine d  b y  the CCITT. Through internationally acc e pted standard interfaces, ISDN provides digi-
tal circuit-switched or packet-switched   communi cations within the network and links to other 
ISDNs to provide national and  international digital communications. See also Integrated Services 
Digital Network Basic Rate Interface and Integrated Services Digital Network Primary Rate 
Interface.
Integrated Services Digital Network Basic Rate Interface (ISDN-BRI)
The interface b etween a communications system and  terminal that in cludes two 64~ kb p s B-chan-
nels for transmitting voice or data and  one 16-kbps D-channel for transmitting  asso ciated  B-chan-
nel call control and out-of-band signaling information (em an arrangement called ‘‘2B(pl1D.’’ 
ISDN-BRI also includes 48~ kb p s for transmitting framing and D-channel contention information, 
for a total interface speed of 192 kbps. ISDN-BRI serves ISDN terminals and digital terminals fit-
ted with ISDN terminal ad a pters. See also Integrated Services Digital Network Primary Rate 
Interface.
Integrated Services Digital Network Primary Rate Interface (ISDN-PRI)
The interface between multiple communications systems that in North America includes 24 
64 ~kbps channels, corresponding to the North American digital signal level-1 (DS1) standard 
rate of 1.544 Mbytes per second.
The most common arrangement of channels in ISDN-PRI is 23 64 ~k bps B-channels for transmit-
ting voice and data and one 64~kbps %D-channel for transmitting asso ciated %B-channel call 
control and out-of-band signaling information (em an arrangement called ‘‘23B(pl1D,’’ although 
with nonfac ility-associated signaling (NFAS) ISDN-PRI can in clude %24 ~B-channels and no 
%D-channel. See also Integrated Services Digital Networkand Integrated Services Digital 
Network Basic Rate Interface.
intercept tone
An tone that indic ates a dialing error or denial of the servi ce requested .
interface
A common boundary between two systems or pieces of equipment.
internal call
A connection between two users within a system.
International Tele-communications Union (ITU)
Formerly known as International Telegraph and Telephone Consultative Committee (CCITT), ITU 
is an international organization that sets universal standards for data communications, including 
Integrated Services Digital Network (ISDN). ITU memb ers are from telecommunications compa-
nies and organizations around the world. See also BX.25.
International Telegraph and Telephone Consultative Committee
See  International Telecommunications Union (ITU).
interflow
Allows calls to forward to other sp lits on the same PBX or a different PBX using the Call Forward 
All Calls switch feature.
intraflow
Allows calls to be redirected to other splits on the same PBX on a conditional or unconditional 
basis using call coverage ‘‘busy,’’ ‘‘don’t answer,’’ or ‘‘all’’ criteria. 
						

							Glossary
Issue  4  September 1995GL-19 
internal measurements
Refers to those BCMS measurements that are made by the system. ACD measurements that are 
made external to the system (via External CMS) are referred to as external measurements.
in-use lamp
A red light on a multiappearance voice terminal that is illuminated to show which call appearance 
will be selected when the handset is lifted or which call appearance is active when a user is 
off-hook.
ISDN Gateway (IG)
A feature allowing integration of the switch and a host-based telemarketing application via a link 
to a gateway adjunct. The gateway adjunct is a 3B-based prod u ct that notifies the host-based 
telemarketing application of call events.
ISDN trunk
A trunk administered for use with Integrated Services Digital Network primary rate interface 
(ISDN-PRI). Also called ‘‘ISDN facility.’’
ISDN-PRI Terminal Adapter
A terminal ad a pter acts as interface between endpoint ap p lications and an ISDN PRI facility. 
ISDN-PRI terminal adapters are currently available from other vendors and are primarily designed 
for video conferencing applications. Accordingly, currently available terminal adapters ad a pt the 
two pairs of vi deo codec   data (V.35) and  d ialing (RS-366) ports to an ISDN PRI facility.
L
light-emitting diode (LED)
A semiconductor device that produces light when voltage is applied. LEDs provide a visual indi-
cation of the operational status of hardware components, the results of maintenance tests, and 
the alarm status of circuit p a cks, and the activation of telephone features.
lightwave transceiver
Hardware that provides an interface to fiber-optic cable from port circuit p a cks and  digital signal 
level-1 (DS1) converter circuit packs. Lightwave transceivers convert electrical signals to light 
signals and vi ce versa.
line
A transmission path between a communi cations system or central office (CO) switching system 
and a voice terminal or other terminal.
line port
The hardware that provides the access point to a communications system for each circuit associ-
ated with a telephone and/or data terminal.
link
A transmitter-receiver channel that connects two systems.
link-access procedure on the D-channel (LAPD)
A link-layer protocol on the Integrated Services Digital Network basi c rate interface (ISDN-BRI) 
and primary rate interfac e (ISDN-PRI) data-link layer (level 2). LAPD provides data transfer 
between two d evices, and error and  flow control on multiple log i cal links. LAPD is used  for signal-
ing and low-speed pac ket data (X.25 and mode 3) on the signaling (D-) channel and for mode-3 
data communications on a bearer (B-) channel. 
						

							Glossary
GL-20Issue  4  September 1995 
local area network (LAN)
A networking arrangement desi gned for a limited geographical area. Generally, a LAN is limited 
in range to a maximum of 6.2 miles and provides high-speed carrier servic e with low error rates. 
Common configurations include daisy chain, star (including circuit-switched), ring, and bus.
logical link
The communications path between a processor and a basic rate interface (BRI) terminal.
loop-start trunk
A trunk on which, after establishing a connection with a distant switching system for an outgoing 
call, the system waits for a signal on the loop formed by the trunk leads before sending the digits 
of the called number.
M
main-satellite-tributary
A private network configuration that can either stand alone or a c cess an electronic tandem net-
work (ETN). A ‘‘main’’ switch provides interconnection, via tie trunks, with one or more subtending 
switches, called ‘‘satellites’’; all attendant positions for the main/satellite configuration; and a ccess 
to and from the public network. To a user outside the complex, a main/satellite configuration 
appears as one switch, with one listed directory number (LDN). A ‘‘tributary’’ switch is connected 
to the main switch via tie trunks, but which has its own attendant positions and LDN.
maintenance
The activities involved in keeping a telecommunications system in proper working condition: the 
d etection and isolation of software and hardware faults, and automatic  and  manual recovery from 
these faults.
management terminal
The terminal that is used by the system administrator to administer the switch. The terminal may 
also be used to ac c ess the BCMS feature.
major alarm
An ind i cation of a failure that has caused critical degradation of service and requires immediate 
attention. Major alarms are automatically displayed  on LEDs on the attendant console and mainte-
nance or alarming circuit pack, logged to the alarm log, and reported to a remote maintenance 
fac ility, if applic a ble.
manual-in work mode
In this mode, agents automatically enter the ACW mode when they dis connect from an ACD call. 
However, in order to become available to receive another ACD call, they must then manually enter 
the Auto-In or Manual-In mode. 
See Auto-In Work Mode for a contrast.
memory
A device into which information can be c o pied and held, and from which the information can be 
obtained at a later time.
message center
An answering service that supplies agents to and stores messages for later retrieval.
message center agent
A member of a message center hunt group who takes and retrieves messages for voice terminal 
users.