General DataComm DeskTop T1 Owner's manual

Data Service Unit
DeskTop T1
GDC 048R154-000-01
Issue 1 - October 1997
Installation and Operation
General DataComm

Table of Contents
GDC 048R154-000
Preface
1 Technical Overview
Overview............................................................................1-1
DT T1 DSU Features.........................................................1-1
Description.........................................................................1-2
Fractional T1 Capabilities..................................................1-2
DTE Interface.....................................................................1-3
2 Installation
Overview............................................................................2-1
Unpacking and Handling ...................................................2-1
Preoperational Check.........................................................2-1
Option Selection.................................................................2-2
Timing Options............................................................2-2
Connections......................................................................2-13
DTE Interface Port Connection.................................2-13
Network Connection..................................................2-13
Primary Power Connection........................................2-15
Terminal Connection.................................................2-15
3 Operation
Overview............................................................................3-1
Controls and Indicators ......................................................3-1
Terminal Interface..............................................................3-3
Configuration...............................................................3-3
Diagnostics ..................................................................3-8

ii Table of Contents
GDC 048R154-000
Monitor ......................................................................3-10
What Are You?..........................................................3-12
4 Tests
Overview............................................................................4-1
Terminal Interface Test Procedure.....................................4-4
Network QRSS Self Test ...................................................4-8
Network Payload Loopback.............................................4-10
Network Line Loopback ..................................................4-11
Network Local Test..........................................................4-13
Network Local Test with QRSS Self Test.......................4-13
Network Remote Test ......................................................4-14
Network Remote Test with QRSS Self Test....................4-16
DTE Self Test...................................................................4-17
DTE Local Loopback.......................................................4-19
DTE Digital Loopback.....................................................4-21
DTE Remote Digital Loopback .......................................4-21
DTE Remote Digital Loopback with Self Test................4-23
A Technical Characteristics
B DTE Interface Signals
C Timing Options
D Alarm Definitions

Table of Contents iii
GDC 048R154-000
Figures
2-1 Position of Configuration Option Switchbanks..........2-3
2-2 Back Panel Connectors...............................................2-13
2-3 EIA-530 Interface Daughter Card Installation............2-14
3-1 DT T1 Front Panel Controls and Indicators................3-2
3-2 Configuration Screen, with Default Settings..............3-4
3-3 Diagnostics Selection Screen......................................3-9
3-4 Diagnostics Results Screen.........................................3-10
3-5 Monitor Screen ...........................................................3-11
3-6 What Are You? Screen ...............................................3-12
4-1 Fault Isolation Procedure............................................4-3
4-2 Diagnostics Selection Screen......................................4-4
4-3 Diagnostics Results Screen.........................................4-7
4-4 Data Path for Network End-to-End Self Test .............4-9
4-5 Network End-to-End Self Test, Front Panel Control..4-9
4-6 Data Path for Network Payload Loopback .................4-11
4-7 Data Path for Network Line Loopback.......................4-12
4-8 Network Line Loopback, Front Panel Control ...........4-12
4-9 Data Path for Network Local Test..............................4-13
4-10 Network Local Test, Front Panel Control...................4-14
4-11 Data Path for Network Remote Test...........................4-15
4-12 Network Remote Test, Front Panel Control ...............4-15
4-13 Data Path for Network Remote Test with Self Test ...4-16
4-14 Network Remote Test with Self Test,
Front Panel Control.....................................................4-17
4-15 Data Path for DTE End-to-End Self Test ...................4-18
4-16 DTE End-to-End Self Test, Front Panel Control........4-19
4-17 Data Path for DTE Local Loopback...........................4-20
4-18 DTE Local Loopback, Front Panel Control................4-20

iv Table of Contents
GDC 048R154-000
4-19 Data Path for DTE Digital Loopback.........................4-21
4-20 Data Path for DTE Remote Digital Loopback............4-22
4-21 DTE Remote Digital Loopback,
Front Panel Control.....................................................4-22
4-20 Data Path for DTE Remote Digital Loopback
with Self Test ..............................................................4-23
4-21 DTE Remote Digital Loopback with Self Test,
Front Panel Control.....................................................4-24
Tables
1-1 Equipment List............................................................1-4
2-1 Option Application Notes – Switchbank S13,
CSU Characteristics....................................................2-4
2-2 Option Application Notes – Switchbank S14,
Network Characteristics..............................................2-6
2-3 Option Application Notes – Switchbank S15,
DTE Characteristics....................................................2-8
2-4 Option Application Notes – Switchbank S10,
DTE Characteristics....................................................2-9
2-5 Option Application Notes – Switchbanks S11 & S12,
DS0 Assignments........................................................2-10
2-6 DTE Data Rate Selection – Switchbank S12..............2-11
2-7 DTE Starting DS0 Selections – Switchbank S11 .......2-12
3-1 DT T1 Configuration Option Settings........................3-5

Preface
GDC 048R154-000
Scope
This manual describes how to install and configure a General
DataComm Desktop T1 Data Service Unit. It is written for installers,
servicetechnicians,andusers.Itassumesa workingknowledgeofdata
interfaces, and T1 and Fractional T1 data transmission services.
Revision History
This is the initial issue of the manual.
Organization
Thismanual has four chaptersandfour appendices. Theinformationis
arranged as follows:
•Chapter 1 - Technical Overview describes the Data Service Unit,
its features, and its options. This chapter contains the Equipment
List table.
•Chapter2 -Installation providesdirectionsfor installingtheDSU
and configuring it by means of the switchbanks located on the pc
board.
•Chapter 3 - Operation describes the use of both the DSU front
panel controlsandindicators,andthe VT100-compatibleterminal
interface that can be accessed through the Console port.
•Chapter 4 - Tests describes tests that can be performed on the
DSU.
•Appendix A - Technical Characteristics
•Appendix B - DTE Interface Signals lists pin/signal assignments
for thetwo DTE interfaces that theDSUcansupport: ITU-T V.35
and EIA-530.
•AppendixC - Timing Options illustratesthearrangementsthat can

vi Preface
GDC 048R154-000
be used to provide transmit timing for the DSU.
•Appendix D - Alarm Definitions identifies the conditions that can
cause the DSU to generate an alarm.
Document Conventions
Level 1 paragraph headers introduce major topics.
Level 2 paragraph headers introduce subsections of major
topics.
Level 3 paragraph headers introduce subsections of sec-
ondary topics.
This typewriter font shows output that
is displayed on the screen.
This bold font shows specific input that
you type at the keyboard.
This bold italicized font shows variable
input that you type at the keyboard.
Service and Support
General DataCommiscommitted toproviding theservice and support
needed to install, manage, and maintain your equipment. For
informationaboutserviceprogramsorforassistancewithyoursupport
requirements, contact your local Sales Representative or call General
DataComm Service at the 24-hour, toll-free number listed below.
• in the U.S. dial 1-800-243-1030
• outside the U.S. dial 1-203-598-7526
Notes present special instructions, helpful hints or
general rules.
NOTE

Preface vii
GDC 048R154-000
Be ready with the site name and phone number, and a description of
the problem. The next available support representative will promptly
return your call.
Hands-ontraining courses areprovidedbyGDCEducationalServices.
Courses range from basic data communications, modems and
multiplexers,to complex networkand ATMsystems and aretaught in
Connecticutor at a customer location.To discusseducationalservices
orreceivea course schedule,call1-800-243-1030andfollowthemenu
instructions.
Safety Instructions
Antistatic Precautions
Electrostatic discharge (ESD) results from the buildup of static
electricity and can cause computer components to fail. Electrostatic
discharge occurs when a person whose body contains a static buildup
touches a computer component.
The equipment may contain static-sensitive devices that are easily
damaged, so proper handling and grounding are essential. Use ESD
precautionary measures when installing parts or cards, and keep the
parts and cardsin antistaticpackagingwhen notinuse. Ifpossible, use
antistatic floor pads and workbench pads.
When handling components or setting switch options always use an
antistatic wrist strap connected to a grounded equipment frame or
chassis. If a wrist strap is not available, periodically touch an
unpainted metal surface on the equipment. Never use a conductive
tool, such as a screwdriver or a paper clip, to set switches.
Safety Guidelines
The following symbols are used in this manual to draw your attention
to potential hazards. A Caution indicates a hazard to equipment or
data. A Warning indicates a hazard to personnel.

viii Preface
GDC 048R154-000
Always use cautionandcommon sense. Toreducetherisk of electrical
shock,do not operate any equipment with the cover removed.Repairs
must be performed by qualified service personnel only.
Regulatory Notices
FCC Part 68 Compliance
Connectionofdatacommunicationsequipmenttothe public telephone
network is regulated by FCC Rules and Regulations. This equipment
complies with Part 68 of these regulations which require all of the
following:
Allconnectionstothetelephonenetworkmustbemadeusingstandard
plugs and telephone company provided jacks or equivalent.
Connection of this equipment to party lines and coin telephones is
prohibited.A label on thebottom of the DT T1 enclosure providesthe
FCC Registration number for the unit. If requested, give this
information to the telephone company.
To connect the DeskTop T1 DSU to the Public Telephone Network
you are required to give the following information to the Telephone
Company:
FCC Registration Number: AG6USA-24144-DE-N
FIC (Facility Interface Code):04DU9-DN,04DU9-BN,04DU9-1KN,
04DU9-1SN
Caution statements identify conditions or practices that
can result in damage to the equipment or in loss of data.
Warning statements identify conditions or practices that
can result in personal injury or loss of life.

Preface ix
GDC 048R154-000
SOC (Service Order Code):6.0Y
Telephone Company jack type:RJ48C
The telephone company may discontinue your servicetemporarily if
theunit causes harm to the telephone network. If possible, youwill be
notifiedofsuch an actionin advance. Ifadvance noticeis notpractical,
you will be notified as soon as possible and will be advised of your
right to file a complaint with the FCC. The telephone company may
change its communication facilities, equipment, operations and
procedures where reasonably required for operation. If so, the
telephone company will notify you in writing. All repairs or
modifications to the equipment must be performed by General
DataComm.Any other repair or modificationby a user voidsthe FCC
registration and the warranty.
Canada DOC Notification
The Canadian Department of Communications label identifies
certifiedequipment.Thiscertificationmeansthattheequipmentmeets
certain telecommunications network protective, operational, and
safety requirements. The Department does not guarantee the
equipment will operate to the user's satisfaction.
Before installing this equipment, users should ensure that it is
permissible to be connected to the facilities of the local
telecommunications company. The equipment must also be installed
using an acceptable method of connection. In some cases, the
company's inside wiring associated with a single line individual
service may be extended by means of a certified connector assembly
(telephone extension cord). The customer should be aware that
compliance withtheaboveconditionsmay not preventdegradation of
service in some situations.
Repairs to certified equipment should be made by an authorized
Canadianmaintenance facility designated by the supplier.Any repairs
or alterations made by the user to this equipment, or equipment
malfunctions, may give the telecommunications company cause to
request the user to disconnect the equipment.
Usersshould ensure for their own protection thatthe electrical ground
connectionsof the power utility,telephonelines,andinternal metallic

x Preface
GDC 048R154-000
water pipe system,if present, are connected together. This precaution
maybe particularly important in rural areas.Users should not attempt
to make such connections themselves, but should contact the
appropriate electric inspection authority, or electrician, as
appropriate.

1 Technical Overview
GDC 048R154-000
Overview
This manual contains instructionsfor installing the DeskTop T1 DSU
and placing it into service.
DeskTop T1 DSU Features
The General DataComm DeskTop T1 Data Service Unit (DSU) is a
highly efficient means of transmitting and receiving digital data over
a T1 line supplied by a telephone company (Telco) or other service
provider. The DeskTop T1 DSU:
• Providesinterfaceto Fractional T1 (FT1) services, givingyou the
flexibility to utilize only the bandwidth you need, from 56 Kbps
up to the full T1 rate of 1.536 Mbps
• Allows the linking of FT1 services with traditional Dataphone
Digital Service (DDS) and generic digital services, including
support for ANSI T1.403 PN 127 loop up/loop down codes.
• Supports one ITU-T V.35-compatible, high-speed, serial data
interface for customer equipment.
• Permitsconfigurationofnetworktransmittertimingfroma variety
of sources:
Timing recovered from network data
External timing
Internal clock
• Supports Extended Superframe (ESF) and D4 framing formats;
also supports unformatted (unframed) operation, for use with
proprietary formats
• Provides configurable Auto Framing option that automatically
adapts the DSU to ESF or D4 format
• With ESF framing selected, supports both TABS Maintenance
Messages (Technical Reference 54016) and ANSI Performance

1-2 Technical Overview
GDC 048R154-000
Report Messages (Bellcore TR-TSY-000194) procedures for
collection and monitoring of network performance information
provided by the Central Office
• Provides independent user and network register sets for TABS
performance data
• SupportsbothAlternateMarkInversion(AMI)andBipolarwith 8
Zero Substitution (B8ZS) line codes, and allows a variety of
options for ones density in the data stream
• Supports a VT100-compatible terminal interface for
configuration, diagnostic, and monitoring functions through the
Console port on the back panel
• Provides T1- and channel-level diagnostics for extensive
diagnostic capabilities
Description
The DeskTop T1 DSU provides interface between the customer's
equipment and a Fractional T1 (FT1) digital carrier facility provided
by the Telco or other carrier. It performs both the Data Service Unit
(DSU) function of converting the customer’s data stream to bipolar
format, and the Channel Service Unit (CSU) functions of network
interfacingand protection.TheDeskTop T1DSU isidealformedium-
sized, low-channel-density networks.
Fractional T1 Capabilities
A T1 line's DS1 signal consists of 24DS0channels. The DeskTop T1
DSU can be configured to map user data into either consecutive or
alternate DS0s to provide rates from 56 Kbps (1 DS0) to 1.536 Mbps
(24DS0sat64Kbpseach).Ratesthatuselessthanthefull1.536Mbps
are referred to as Fractional T1 (FT1).
The output rates available from the DSU are multiples of 56 and 64
Kbpsbecause each of theT1 line's 24 DS0s provides a data rate of 56
or64Kbpsdepending ontheform of linecodingbeingused.TheDSU
can be configured to start a group of DS0son any DS0 in the T1 line.

Technical Overview 1-3
GDC 048R154-000
The full T1 bandwidth is available when consecutive DS0s are used,
butrestrictionsononesdensity maylimit theactual usablebandwidth.
Use of consecutive DS0sfor N x64 KbpsrequireseitherB8ZS coding
on the network line or provisioning in the DTE to guarantee mark
density requirements.
Using alternate DS0s reducestheT1bandwidth availablefor user data
by one-half, but it eliminates restrictions on the content of user data.
When the DSU is configured to use alternate DS0s it maintains
minimum ones density at 50% by filling the unused DS0s with ones.
DTE Interface
The DeskTop T1 DSU provides DTE interface through an ITU-T
V.35-compatible port for connection to synchronous serial customer
equipment. Examples of customer equipment are Front End
Processors(FEPs), LocalAreaNetwork (LAN) bridges,video codecs,
CAD/CAM workstations, and Group 4 facsimile equipment.

1-4 Technical Overview
GDC 048R154-000
Table 1-1 Equipment List
Description GDC Part No.
GDC DeskTop T1 DSU, 117 V ac, V.35 channel
interface 048A102-005
Power Supply
Power supply, 19 Vac, 0.6A, 60 Hz wall mount
transformer 700-053-002
Cables
Interface cable, ITU-T V.35 34-pin male-to-male
(DSU channel portto customer equipment) (5- to 50-
foot lengths)
027H570-XXX
DCE-to-DCE crossover interface cable, V.35 34-pin
male to 34-pin male 027H521-XXX
Interface cable, RJ48C plug-to-plug (DSU network
port to the T1 line) (10- to 50-foot lengths; 10-foot
length included with standalone enclosure models)
022H024-XXX
Interface cable, RJ48C plug-to-15-pin male (DSU
network port to the T1 line, Canadian installation
only) (10- to 50-foot lengths)
022H022-XXX
Interface cable, RJ48C plug to 15-pin female (DSU
network port to the T1 line, for Canadian installation
only) (10- to 125-foot lengths)
022H020-XXX
Adapter, RS-232 DB25 male to RS-561 8-pin modu-
lar jack (connects to VT100-compatible terminal to
support connection ofinterface cable 830-028-XXX)
029H210-001
Interface cable, RS-561 8-pin modular plug to plug
(connectsDSU Console port to adapter 029H210-
001)
830-028-8XX

2 Installation
GDC 048R154-000
Overview
This chapter describes the installation of the DeskTop T1 DSU.
The DeskTop T1 DSU is shipped pre-assembled, tested, and ready to
use. The normal procedure after unpacking the unit is to connect it to
ac power and perfom the Preoperational Check described in this
chapter. When the test is successfully completed you may proceed to
make cable connections to the DSU.
The DeskTop T1 DSU should be installed in a ventilated area where
theambient temperaturedoesnot exceed 122°F (50°C). Do not install
the DSU above other equipment that generates large amounts of heat
(e.g., power supplies).
Thischapter includes information on setting configuration optionsfor
the DSU by means of the hardware switchbanks located on the pc
board.
Unpacking and Handling
The DeskTop T1 DSU is shipped in packing material that is enclosed
in a corrugated box. Inspect the DeskTop T1 DSU when you receive
it. If you observe any damage, notify the shipper immediately.
Donot discard thebox and packingmaterial. Save them for use if it is
ever necessary to reship the DeskTop T1 DSU.
Preoperational Check
You should give the DeskTop T1 DSU a preoperational check before
you connect it to the network or customer equipment, and before you
change any factory-set options. The factory default setting for all
options is all switches set to Off. Perform a Local Test with Self-Test
to verify normal operation. Refer to Chapter 4 for instructions on
performing the test. Perform the test on the DeskTop T1 DSU before
you connect it to anything other than ac power.

2-2 Installation
GDC 048R154-000
If the DeskTop T1 DSU doesnot check out properly, replace it with a
spare, if available, and repeat the test. Do not attempt to repair the
DeskTop T1DSU.Forassistance, contactGeneral DataCommService
as described in the Preface.
If the DeskTop T1 DSU passes the test but subsequently fails to
perform in datacommunicationsoperation,itmaynotbeatfault; some
error may have been made in the installation or option selection, or
there may be other faulty devices or connections. Recheck the
connections and option selections, and if necessary perform the Fault
Isolation Procedure in Chapter 4 to isolate the fault. Also verify that
the customer equipment and remote DSU are compatible (that is,
operating at the same rate).
Option Selection
The DeskTop T1 DSU provides a number of field-selectable options
by which you can adapt it to a variety of configurations. The most
convenientwaytosetoptionsis tousetheVT100-compatibleterminal
interface. Directions for connecting to the back panel Console port
appear in this chapter; directions for using the terminal interface
appear in Chapter 3, Operation.
You can also make option selections by positioning switches on the
DSU pc card. Figure 2-1 illustrates the locations of the option
switchbanks. The options are described in Tables 2-1, 2-2, 2-3, 2-4,
and 2-5.
Timing Options
Timing options determine the clock source for the data the DeskTop
T1 DSU transmits to the network and receives from the customer
channel equipment. The default timing option for theDSU is Receive
timing, in which the network provides the timing source.
a. If the Auto Framing option is to be used, enable it at only
one of the two DSUs thatmake up a link.
b. If you connect two DSUs back-to-back (direct cable
connection) and automatic Line Build-Out is to be used,
enable it in only one of the DSUs.

Installation 2-3
GDC 048R154-000
Although the network clock is the preferred timing source, the
DeskTopT1DSU providesother timingoptionsforuse in applications
where a network clock is either not available or not applicable. The
flexibility and complexity of the DSU’s timing options require
detailedexplanations.RefertoAppendixC fordetails andapplications
of the DeskTop T1 DSU timing options.
.
Figure 2-1 Position of Configuration Option Switchbanks on
DeskTop T1 PC Card
12345678
ON
1234
ON
12345678
ON
12345678
ON
12345678
ON
12345678
ON
S13 S14 S15
S10 S11 S12
Front Edge of PC Board

2-4 Installation
GDC 048R154-000
Table 2-1 Option Application Notes — Switchbank S13, CSU
Characteristics
(Continued on next page)
Option Selection Switch Position Description
Configuration
Mode Soft S13-1 Off* DSU can be configured by a VT100-compatible terminal
connected to the Console port.The
positions of other switches may
not reflect the actual configuration
of the unit when this is selected.
View the terminal interface
Configuration screen for current
settings.
Hard S13-1 On DSU can only be configured by
means of pc board hardware
switches
Line Framing ESF* S13-2
S13-3 Off* Off Selects ESF Framing
D4 S13-2
S13-3 Off On Selects D4 Framing
Unframed S13-2
S13-3 On Off Selects unframed data transmission
Auto
Framing S13-2 S13-3 On On Enables Auto Framing; the Desk- Top T1 DSUadapts to either ESF
or D4 framing based on the signal
it receives.
Caution:
Do not enable Auto Framing for
both DSUs on a link.
Network Line
Type DS-1 S13-4 Off* Selects the line interface to operate as a DS-1 network interface for
connection to a T1 line.
DSX-1 S13-4 On Selects the line interface to operate
as a DSX-1 interface for
connection to the cascade port of
another DSU or to a CSU.
* Factory default selection.