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Chapter 1
Introduction
1.1 Introduction
1.2 About Telephone Trunks
1.2.1 Analog Trunks
1.2.2 Digital Trunks
1.3 Trunk Interface Boards
1.3.1 Trunk Interface Boards and the MVIP Bus
1.4 About CAS Protocol Software
1.5 Protocols and CT Access
1.5.1 About Trunk Control Programs (TCPs)
1.5.2 Parameter Files
1.6 Protocol Software Package Contents
1.6.1 Trunk Control Programs (TCPs)
1.6.2 About AG Configuration and Parameter Files
1.6.3 Binary Parameter Category Definition Files
1.6.4 ASCII Parameter Value Definition Files
1.6.5 SLAC Files
1.1 Introduction
This chapter:
Summarizes analog loop start
and digital T1 and E1 trunks.
Explains how AG 2000/4000, AG-T1/E1 and AG Quad/Dual boards are used in computer telephony applications.
Discusses protocol software, and its role in a computer telephony application.
Lists and describes the other software components required in a computer telephony application.
Provides broad outlines for developing computer telephony applications that use CAS protocols.
1.2 About Telephone Trunks
This section describes the types of line interface boards used to connect to telephone networks.
1.2.1 Analog Trunks
Analog trunks with loop start signaling are the most common type of telephone trunks found in residential installations. The network uses the presence or absence of current flow in the telephone circuit as signaling information when establishing and processing connections.
1.2.2 Digital Trunks
Digital trunks multiplex the signal of many different channels into one interface. Digital trunks follow two basic standards around the world:
T1 trunk lines have a capacity of 1.544 Mbps, and typically handle 24 simultaneous telephone channels. T1 trunks are used in the United States, Canada, Hong Kong, and Japan.
E1 trunk lines have a capacity of 2.048 Mbps and typically handle 30 simultaneous telephone channels. E1 trunks are used mainly in Europe, Asia and South America.
Digital trunks use signaling bits associated with voice channels to carry signaling information. For a detailed description of T1 and E1 communications, see the appropriate board installation and developer's manual.
1.3 Trunk Interface Boards
NMS provides a variety of trunk interface boards for connecting to public switched telephone networks (PSTNs). The boards discussed in this manual include:
AG-8 and AG 2000 boards
AG-T1/E1 boards
AG Quad/Dual boards
AG 4000 boards
1.3.1 Trunk Interface Boards and the MVIP Bus
NMS trunk interface boards can connect to other boards in the same chassis over the CT bus. The CT bus is a high-speed, time-division multiplexed digital telephony bus between telephone line interface boards (such as AG 2000 and AG Quad boards), that allows boards to share data, signaling, and switching information. You can add additional DSP resources, analog line interfaces, or loop start line interfaces, by using other AG 2000 and Quad boards or board sets.
You can also use MVIP-compatible products from other manufacturers with the AG 2000, AG-8, AG-T1/E1, AG Quad boards, or AG 4000 boards.
AG 2000 and AG-8 Boards
NMS AG 2000 and AG-8 boards provide eight analog line interfaces with up to 8 ports of call processing and programmable voice processing.
The AG-8 board carries two C51 digital signal processors (DSPs), that allow it to perform call control and voice processing on all telephony channels simultaneously. The AG-8 connects to the host PC through its ISA bus.
The AG 2000 carries one to four high-performance C549 digital signal processors (DSPs). The AG 2000 board connects with the host PC through a PCI bus slot, and fully supports the H.100 bus specification for switching.
AG-T1 and AG-E1 Boards
AG-T1/E1 and AG Quad boards connect personal computers to T1 or E1 trunks. AG-T1 and E1 boards supply 24 or 30 ports of call processing and carry six C51 DSPs, and connect with the host PC through an ISA bus.
AG Dual and Quad Boards
AG Dual and Quad E and T boards provide between two and four T1 or E1 trunk interfaces for up to 120 ports of call processing and 60 ports of programmable voice processing. These boards carry eight C51 DSPs, and connect with the host PC through a PCI bus.
AG 4000 Boards
AG 4000 E and T boards provide one, two or four T1 or E1 trunk interfaces for up to 120 ports of call processing and programmable voice processing. They carry up to 16 high-performance C549 DSPs, and connect with the host PC through a PCI bus.
For detailed information about a particular AG board, refer to the appropriate board installation and developer's manual.
WARNING:
Natural MicroSystems obtains board-level approval certificates for supported countries. Some countries require that you obtain system-level approvals before connecting a system to the public telephone network. To learn what approvals you require, contact the appropriate regulatory authority in the target country.
1.4 About CAS Protocol Software
To communicate across a trunk line, parties must signal one another. The scheme used to signal across a telephone line is called a
protocol
. Many different protocol standards are in use throughout the world.
The AG CAS package includes:
Analog Loop Start
protocols (LPS)
This protocol family includes protocols which use loop start signaling, where the presence or absence of current flow is interpreted by a switch as protocol signaling events.
Australian P2
protocols (AP2)
This protocol is used in Australia for connections between PBX's and some PSTN carriers. It uses two-bit line signaling (derived from CCITT recommendation Q.421), and in-band DTMF register signaling.
Digital and Analog Wink Start protocol
(WNK)
This protocol family includes protocols used on T1 in the USA, Hong Kong and Taiwan. The protocol uses one-bit signaling, two-bit signaling, or presence or absence of current, and owes its name to the "wink" (brief presence of current or variation of the signaling bit) that the inbound side uses to acknowledge line seizure. Register signaling is performed by in-band DTMF or MF tones, or by out-of-band decadic pulses.
European Digital Channel Associated Signaling
protocol (EUC)
This protocol family includes channel associated signaling protocols used in certain European countries. The protocols use two-bit line signaling specified by national standards for use over E1 trunks. The register signaling is either carried by in-band DTMF tones (not compelled) or by out-of-band decadic pulses.
Feature Group D
protocols (FGD)
The FGD protocol implements the specifications of the Feature Group D (FGD) switched access service. This service provides interconnection to the BOC (Bell Operating Companies) network for the provision of message telecommunications service/wide area telecommunications service (MTS/WATS) and MTS/WATS-type services. FGD service, which provides access to the trunk side of suitably equipped BOC switching systems, is available for termination and originating access.
Ground Start
protocol (GDS)
Natural MicroSystems ground start protocols cover digital interfaces, T1 trunks, connected to a private branch exchange (PBX) or PSTN switches. The protocol can handle two signaling variations: FX (foreign exchange), and SA (special access).
MF-Socotel
protocol (MFS)
This protocol conforms to the Spanish National Specifications for Channel Associated Signaling over E1 trunks. It uses single bit steady-state line signaling, and MF-Socotel MF compelled in-band register signaling.
M
ulti-Frequency Compelled
protocols based on the R2
standard (MFC)
This protocol family includes the CCITT Signaling System R2 (Recommendations Q.421 to Q.442, CCITT Blue Book, 1988) implementation and numerous national variations. These protocols run on E1 trunks and use two-bit line signaling on the signaling channel associated with each voice channel, and in-band MF compelled register signaling.
Off-Premises Station
protocols (OPS)
The Natural MicroSystems OPS protocol covers only digital interfaces. The protocol can handle T1 or E1 digital trunks, of signaling types FX (foreign exchange) or SA (special access).
Operator Workstation
protocol (STA)
This protocol is the "other side" of the analog loopstart protocol. It is used to implement stations that connect to analog phones.
Pulsed E & M
protocol
(EAM
)
This protocol family includes country-specific protocols which use one-bit line signaling in a pulsed form, and variations on the compelled in-band MF register signaling specified by the CCITT in the 1988 Blue Book. These protocols run on E1 trunks and are specified in different countries by national regulatory agencies.
Signaling System 5
protocol (SS5)
This protocol is specified by the CCITT Recommendations Q.140 to Q.154 (CCITT Red Book, Volume VI Fascicle VI.2, Geneva 1985). The protocol uses in-band compelled signal frequency tones to perform line signaling and in-band MF tones for register signaling. Since no signaling bits are used, this protocol works the same way on T1 and E1 trunks.
System R1.5
protocols (R15)
This protocol family includes channel associated signaling protocols used for E1 lines in Russia (based on CCITT recommendations Q.511 and Q.544). The protocols use two-bit steady-state line signaling. Register signaling is either carried by in-band MF tones (MF acknowledged pulses) or by out-of-band decadic pulses. Two R15 protocol software modules are included with the NMS CAS software package. One is used (
r150
) for controlling inbound calls and the other (
r151
) is used for controlling outbound calls.
Most of the protocols in these families have country-specific variations. NMS provides parameter files that determine how protocols interact with telephone networks in different countries. The package for each country contains software modules you need to download in order to enable telephony boards to communicate with telephone networks in that country.
1.5 Protocols and CT Access
CT Access
(Computer Telephony Access) is a development environment providing standard programming interfaces for telephony functions that are hardware-independent. Within CT Access, logically related telephony functions are subdivided into groups, or
services
. Call control is one such group. The service responsible for call control under CT Access is called the
Natural Call Control
(
NCC
) service.
1.5.1 About Trunk Control Programs (TCPs)
The NCC service provides a powerful call control API, which allows an application to establish inbound or outbound calls, and perform call transfer, blocking, and other operations. To keep this API relatively simple and
protocol-independent, the actual communication with the trunk is performed by another software entity, called a
trunk control program
(
TCP
). The TCP translates commands from the NCC service into signaling appropriate for the particular protocol running on the trunk, and translates protocol-specific trunk events into NCC service events. (See
Figure 1
.)
Figure 1. The TCP's Role in an Application
One or more TCPs is provided for each protocol. You load the TCP into the on-board memory of a line interface board. For applications that must simultaneously support multiple protocols and/or protocol variations, more than one TCP can be loaded to the telephony board at the same time. Each line supports one TCP at a time.
The TCPs to be loaded for an application are specified in the AG configuration file (described in
Section 3.1
). When you run the
agmon
board configuration and monitoring utility, it downloads the specified TCPs to the board. For more information about
agmon
, see your
AG Runtime Configuration and Developer's Manual
.
1.5.2 Parameter Files
Each country uses its own variation of a protocol. In addition to the basic TCP software, each protocol software package contains several binary parameter files
(
.pf
files), each of which programs the TCP for a particular country or network variation. CT Access applications load these parameters automatically at initialization time.
The majority of the parameters specified in TCP parameter files cannot be changed without violating national regulatory laws. However, you can change a subset of these parameters based on the needs of your application. For more information about loading parameters, refer to
Chapter 4
. For information about parameters for each protocol, refer to Chapters 6 - 18.
WARNING:
You may only change a subset of parameters for each CAS protocol without affecting regulatory approvals.
Chapters 6 - 18 list all parameters for each protocol and indicate which parameters may be edited. Editing other parameters may result in violations of country-specific regulations.
1.6 Protocol Software Package Contents
The software package for a given country-specific protocol includes:
readme
file
(
common for all protocols and countries
)
One or more trunk control programs (TCPs)
Four country-specific binary parameter file
Four editable (ASCII) country-specific parameter file
Sample country-specific
agmon
configuration files
One or more SLAC files (for AG 2000 boards)
Each installed protocol includes all of these components. When you install multiple protocols or install protocols for multiple countries, several versions of each component are created.
Note:
To ensure backwards compatibility, the AG CAS for NCC software package contains components to support AG CAS protocols for the ADI service. For this reason, the AG CAS for NCC protocols package contains a binary parameter file and an editable parameter file for ADI service functionality. These files (
adi
<
prt
>.
pf
and
adi
<
prt
>.
par
) are not used by the NCC service.
CT Access includes several call control demonstration programs that can use any of the AG CAS protocols to place or receive calls. Please refer to the
Natural Call Control Service Developer's Reference Manual
for more information about running these programs.
1.6.1 Trunk Control Programs (TCPs)
CAS TCPs include the following:
Protocol
File name
Analog Loop Start
lps0.tcp
Australian P2
ap20.tcp
Digital and Analog Wink Start
wnkx
(
x
=0,1)
European Digital CAS
euc0.tcp
Feature Group D
fgd0.tcp
Ground Start
gds0.tcp
MF-Socotel
mfs0.tcp
MFC-R2
mfc0.tcp
Off-Premises Station
ops0.tcp
Operator Workstation
sta0.tcp
Pulsed E and M
eam0.tcp
Signaling System 5
ss50.tcp
System R1.5
r150.tcp
,
r151.tcp
1.6.2 About AG Configuration and Parameter Files
AG configuration files contain information that determines how
agmon
sets up AG boards. These files also contain country-specific information for different protocols.
File name
Location
Description
ag<
prt
>.cfg
Windows NT:
\nms\ag\cfg
UNIX:
/opt/nms/ag/cfg
The default example AG configuration file to configure one board with all the modules and settings to run protocol <
prt
>. It reflects the last country installed in the system for the protocol <
prt
>. For AG-8, AG-T1,
AG-E1, AG 2000.
ag<
prt
><
cty
>.cfg
Windows NT:
\nms\ag\cfg\country
UNIX:
/opt/nms/ag/cfg/country
The example AG configuration file to configure one board with all the modules and settings to run protocol <
prt
> in the country <
cty
>. A different file is installed for each country. For AG-8, AG-T1,
AG-E1, AG 2000.
q
<
prt
>
.cfg
Windows NT:
\nms\ag\cfg
UNIX:
/opt/nms/ag/cfg
The default example AG configuration file to configure one board with all the modules and settings to run protocol <
prt
>. It reflects the last country installed in the system for the protocol <
prt
>. For AG Quad and Dual T1 and AG Quad and Dual E1.
q
<
prt
><
cty
>.
cfg
Windows NT:
\nms\ag\cfg\country
UNIX:
/opt/nms/ag/cfg/country
The example AG configuration file to configure one board with all the modules and settings to run protocol <
prt
> in the country <
cty
>. A different file is installed for each country. For AG Quad and Dual T1 and AG Quad and Dual E1.
a4<
prt
>.cfg
Windows NT:
\nms\ag\cfg
UNIX:
/opt/nms/ag/cfg
The default example AG configuration file to configure one board with all the modules and settings to run protocol <
prt
>. It reflects the last country installed in the system for the protocol <
prt
>. For AG 4000 boards.
a4<
prt
><
cty
>.cfg
Windows NT:
\nms\ag\cfg\country
UNIX:
/opt/nms/ag/cfg/country
The example AG configuration file to configure one board with all the modules and settings to run the protocol <
prt
> in the country <
cty
>. A different file is installed for each country. For AG 4000 boards.
Where <
prt
> indicates the protocol and <
cty
> indicates the country where used.
For more information about AG configuration files, refer to the
AG Runtime Configuration and Developer's Manual
or
Chapter 3
of this manual.
1.6.3 Binary Parameter Category Definition Files
Binary parameter files contain the complete set of country-specific parameters and default values. These files are loaded by CT Access at
initialization
time. There are four types of binary parameter category definition files:
File name
Location
Description
nccx<
prt
>.pf
Windows NT:
\nms\ag\cfg
UNIX:
/opt/nms/ag/cfg
Defines the CT Access parameter category
NCC.X.ADI_
<
prt
>. This category holds all protocol-specific parameters for the <
prt
> protocol. The parameter default values defined by these file apply to the TCP implementing the protocol <
prt
> for the last country installed.
nccxadi.pf
Windows NT:
\nms\ag\cfg\
UNIX
/opt/nms/ag/cfg
Defines the CT Access parameter category
NNC.X.ADI_START
and
NCC.X.ADI_PLACECALL
. These parameter categories include all the country-specific parameters for boards in the AG family.
nccstart.pf
Windows NT:
\nms\ag\cfg
UNIX:
/opt/nms/ag/cfg
Defines the CT Access parameter category
NCC.START
.
NCC.START
parameters include all the country-specific parameters for the last country installed.
adi<
prt
>.pf
Windows NT:
\nms\ag\cfg
UNIX:
/opt/nms/ag/cfg
Provides for backwards compatibility for applications that use the ADI service for call control. It defines the CT Access parameter category
ADI
<
prt
> which contains all the protocol-specific parameters for the <
prt
> protocol. The parameter default values defined by these file apply to the TCP implementing the protocol <
prt
> for the last country installed.
Where <
prt
> indicates the protocol and <
cty
> indicates the country where used.
Note:
Installing another country variation of a specific protocol overwrites the
nccx
<
prt
>
.pf
and
adi
<
prt
>
.pf
files.
Binary Parameter File Backups
When you install AG CAS for Natural Call Control software, the installation program installs the following backup copies of binary parameter files.The following table provides the names and locations of these backup files:
Binary parameter file
Backup file
Backup file location
nccx<
prt
>.pf
nccx<
prt
><
cty
>.pf
Windows NT:
\nms\ag\cfg\country
UNIX:
/opt/nms/ag/cfg/country
nccxadi.pf
nccxadi<
cty
>.pf
Windows NT:
\nms\ag\cfg\country
UNIX:
/opt/nms/ag/cfg/country
nccstart.pf
nccstart<
cty
>.pf
Windows NT:
\nms\ag\cfg\country
UNIX:
/opt/nms/ag/cfg/country
adi<
prt
>.pf
<
prt
><
cty
>.pf
Windows NT:
\nms\ag\cfg\country
UNIX:
/opt/nms/ag/cfg/country
Where <
prt
> indicates the protocol and <
cty
> indicates the country where used.
1.6.4 ASCII Parameter Value Definition Files
ASCII parameter value definition files can be used to reset the values of the country specific parameters. Some of the parameters values may be changed without affecting the regulatory approvals in the target country.
These files can be used to set the parameter values system-wide, using the CT daemon, or it can be parsed by the application for dynamic parameter management with CT Access functions.
Parameters within the ASCI parameter files fall within two classes:
Those that can be changed by the user to fit the application's needs
Those that should not be changed because they have regulatory relevance.
There are four types of ASCII parameter value definition files:
File name
Location
Description
nccx<
prt
>.par
Windows NT:
\nms\ctaccess\cfg
UNIX:
/opt/nms/ctaccess/cfg
This file defines the CT Access parameter category
NCC.X.ADI_
<
prt
>. This category holds all
protocol-specific parameters for the <
prt
> protocol. The parameter default values defined by these file apply to the TCP implementing the protocol <
prt
> for the last country installed.
nccxadi.par
Windows NT:
\nms\ctaccess\cfg\
UNIX
/opt/nms/ctaccess/cfg
This file defines the CT Access parameter category
NNC.X.ADI_START
and
NCC.X.ADI_PLACECALL
. These parameter categories include all the country-specific parameters for boards in the AG family.
nccstart.par
Windows NT:
\nms\ctaccess\cfg
UNIX:
/opt/nms/ctaccess/cfg
Defines the CT Access parameter category
NCC.START
.
NCC.START
parameters include all the country-specific parameters for the last country installed.
Note:
Installing another country variation of a specific protocol overwrites the
nccx
<
prt
>
.par
and
adi
<
prt
>
.par
files.
Backups of ASCII parameter files are kept in the
\nms\ctaccess\cfg\country
(under Windows NT) or
/opt/nms/ctaccess/cfg/country
(under Unix) directory. These files are named in the same way as the binary file backup files, except that the file name include a three letter string <
cty
> that specifies the country where used.
For more information about editable parameters for each CAS protocol, refer to Chapters 6 - 18.
1.6.5 SLAC Files
SLAC files contain information that must be loaded into the QSLAC devices of AG 2000 boards so that the board line interface is appropriate for country-specific line conditions.
For more information about the SLAC files, refer to the
AG 2000 Installation and Developer Manual
. Refer to Appendix C for the list of SLAC files available for different countries.
File name
Location
Description
<
pp
><
cty
><
ss
><
i
>.slc
Windows NT:
\nms\ag\load
UNIX:
/opt/nms/ag/load
File that programs the QSLAC devices on <
pp
> boards to implement the analog specifications of country <
cty
>, for the signaling protocol <
ss
> and with a line impedance <
i
>. Only one file per configuration is installed. SLAC files are referenced by the AG configuration files installed for the signaling protocol <
ss
> in country <
cty
>.
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