Patton electronics 2710 User manual

USER
MANUAL
MODEL 2710 Series
NetLink-T1™
T1/FractionalT1
CSU/DSU
SALES OFFICE
[phone]
TECHNICAL SUPPORT
[phone]
Part# 07M2710
Doc# 08604U2-001,
Rev. D
Revised 4/4/08
An ISO-9001
Certified
Company
CERTIFIED

2
TABLE OF CONTENTS
1.0 COMPLIANCE INFORMATION ................................................... 4
1.1 Warranty Statement...................................................................... 4
1.2 CE Notice...................................................................................... 4
1.3 Radio and TV Interference............................................................ 5
1.4 FCC Information ........................................................................... 5
FCC Compliance .......................................................................... 6
1.5 Industry Canada Notice : .............................................................. 6
1.6 Service Information....................................................................... 7
2.0 GENERAL INFORMATION.......................................................... 8
2.1 Features........................................................................................ 8
2.2 Description.................................................................................... 8
2.3 Supported Applications................................................................. 9
The 2710 as the Interface between the Telco and CPE............... 9
The 2710 as a High-Speed Short Range Modem ........................ 9
3.0 CONFIGURATION ..................................................................... 10
3.1 DIP Switch Configuration............................................................ 10
Switches SW1, SW2, and SW3.................................................. 11
Switch SW4: Line Framing and Coding..................................... 11
Line Framing Options: ......................................................... 12
Line Coding Options: ........................................................... 12
Switch SW5: DS0 Channel Rate ............................................... 12
Switch SW6: Clock Mode .......................................................... 12
Switches SW7 and SW8: Line Build Out................................... 13
3.2 Software Configuration ............................................................... 14
Introduction to Main Menu.......................................................... 15
System Configuration ................................................................. 16
System Diagnostics.................................................................... 23
Network Interface (NI) STATUS .......................................... 26
Valid Interval Count & Current Interval Time ....................... 27
Error Counters ..................................................................... 27
Rx PRM ............................................................................... 28
Current DIP Switch Settings ................................................ 28
Unit Options................................................................................ 29
4.0 INSTALLATION ......................................................................... 31
4.1 DTE Interface Connection .......................................................... 31
4.2 Network Interface Connection .................................................... 31
4.3 Power Connection ...................................................................... 32
Using the AC Power Supply (120VAC or 100-240VAC)............. 32
Supplying DC Power .................................................................. 32
Supplying Power via pin KK ....................................................... 32
5.0 OPERATION .............................................................................. 33
5.1 LED Descriptions ........................................................................ 33
5.2 Loop (V.54 & Telco) Diagnostics ................................................ 35
Operating Local Loopback (LL) .................................................. 35

3
Operating Remote Digital Loopback (RL)................................... 35
Central Office Loops................................................................... 36
5.3 Bit Error Rate (V.52) Diagnostics................................................ 37
A
Specifications ........................................................................... 38
B
Cable Recommendations......................................................... 39
C
Factory Replacement Parts and Accessories........................ 40
D
Interface Pin Assignment........................................................ 41
D.1 RJ-48C T1 (DS0) Network Interface (Female Modular Jack) ..... 41
D.2 TRS Jack (RS-232 Control Port) .................................................. 41
D.3 RS-232 Control Port (Signals at DB-25 Connector) .................... 41
D.4 RS-232 Control Port (Signals at DB-9 ConnectOr) ..................... 41
D.5 M/34 Connector, Terminal Interface ........................................... 42
E
Power Supply Interface ............................................................ 43

4
1.0 COMPLIANCE INFORMATION
Thank you for purchasing this Patton Electronics product. This product
has been thoroughly inspected and tested and is warranted for One Year
parts and labor. If any questions or problems arise during installation or
use of this product, please do not hesitate to contact Patton Electronics
Technical Support at [phone].
1.1 WARRANTY STATEMENT
Patton Electronics warrants all Model 2710 Series components to be free
from defects, and will—at our option—repair or replace the product
should it fail within one year from the Þrst date of shipment.This warranty
is limited to defects in workmanship or materials, and does not cover
customer damage, abuse, or unauthorized modiÞcation. This product
contains no serviceable parts; therefore the user shall not attempt to
modify the unit in any way. If this product fails or does not perform as
warranted, your sole recourse shall be repair or replacement as
described above. Under no condition shall Patton Electronics be liable
for any damages incurred by the use of this product. These damages
include, but are not limited to, the following: lost proÞts, lost savings and
incidental or consequential damages arising from the use of or inability to
use this product. Patton Electronics speciÞcally disclaims all other war-
ranties, expressed or implied, and the installation or use of this product
shall be deemed an acceptance of these terms by the user. In the event
the user detects intermittent or continuous product malfunction due to
nearby high power transmitting radio frequency equipment, the user is
strongly advised to use only data cables with an external outer shield
bonded to a metal or metalized connector.
1.2 CE NOTICE
The CE symbol on your Patton Electronics equipment indicates that it is
in compliance with the Electromagnetic Compatibility (EMC) directive
and the Low Voltage Directive (LVD) of the Union European (EU). A Cer-
tiÞcate of Compliance is available by contacting Patton Technical Sup-
port.
This device is not intended to be connected to the public
telephone network in Europe.
WARNING

5
1.3 RADIO AND TV INTERFERENCE
The NetLink-T1™ Model 2710 Series generates and uses radio fre-
quency energy, and if not installed and used properly—that is, in strict
accordance with the manufacturer's instructions—may cause interfer-
ence to radio and television reception. The Model 2710 Series has been
tested and found to comply with the limits for a Class A computing device
in accordance with the speciÞcations in Subpart J of Part 15 of FCC
rules, which are designed to provide reasonable protection from such
interference in a commercial installation. However, there is no guarantee
that interference will not occur in a particular installation. If the Model
2710 Series does cause interference to radio or television reception,
which can be determined by disconnecting the cables, the user is
encouraged to try to correct the interference by one or more of the follow-
ing measures: moving the computing equipment away from the receiver,
re-orienting the receiving antenna, and/or plugging the receiving equip-
ment into a different AC outlet (such that the computing equipment and
receiver are on different branches).
1.4 FCC INFORMATION
The Model 2710 Series has been tested and registered in compliance
with the speciÞcations in Part 68 of the FCC rules. A label on the equip-
ment bears the FCC registration number. You may be requested to pro-
vide this information to your telephone company.
Your telephone company may make changes in its facilities, equipment,
operations or procedures that could affect the proper operation of the
Model 2710 Series. If this happens, the telephone company should give
you advance notice to prevent the interruption of your service.
The telephone company may decide to temporarily discontinue your ser-
vice if they believe your Model 2710 Series may cause harm to the tele-
phone network. Whenever possible, they will contact you in advance. If
you elect to do so, you have the right to Þle a complaint with the FCC.
If you have any trouble operating the Model 2710 Series, please contact
Patton Technical Support at [phone]. The telephone company
may ask you to disconnect the equipment from the telephone network
until the problem has been corrected or until you are certain that the
Model 2710 Series is not malfunctioning.
The following information may be required when applying to your local
telephone company for leased line facilities:

6
FCC Compliance
The Model 2710 has been tested and found to comply with the speciÞca-
tions found in Part 68 of the FCC rules and regulations. A label on the
equipment bears the FCC registration number. You may be requested to
provide this information to your telephone company.
The telephone company may decide to temporarily discontinue your ser-
vice if they believe that the Model 2710 may cause harm to the telephone
network. Whenever possible the telephone company will attempt to
notify you in advance. You have a right, if you so choose, to Þle a com-
plaint with the FCC.
In accordance with FCC rules and regulation CFR 47 68.218(b)(6), the
user must notify the telephone company prior to disconnection.
The Universal Service Order Code (USOC) is RJ48.
The Facility Interface Codes (FIC) are 04DU9-BN, 04DU9-DN, 04DU9-
1KN, and 04DU9-1SN.
The Service Order Code (SOC) is 6.0N
1.5 INDUSTRY CANADA NOTICE :
The Canadian Department of Communications label identiÞes certiÞed
equipment. This certiÞcation means that the equipment meets certain
telecommunications network protective, operational and safety require-
ments. The Department does not guarantee the equipment will operate
to the user's satisfaction.
Before installing this equipment, users should ensure that it is permissi-
ble to be connected to the facilities of the local telecommunications com-
pany. 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 certi-
Service Facility Interface
Code
Service
Code Network Connection
1.544 Mbps SF format without line power 04DU9-BN 6.0N RJ48C
1.544 Mbps SF and B8ZS without line
power 04DU9-DN 6.0N RJ48C
1.544 Mbps ANSI ESF without line power 04DU9-1KN 6.0N RJ48C
1.544 Mbps ANSI ESF and B8ZS w/o line
power 04DU9-1SN 6.0N RJ48C

7
Þed connector assembly (telephone extension cord). The customer
should be aware that compliance with the above condition may not pre-
vent degradation of service in some situations.
Repairs to some certiÞed equipment should be made by an authorized
maintenance facility designated by the supplier. Any repairs or alter-
ations made by the user to this equipment, or equipment malfunctions,
may give the telecommunications company cause to request the user to
disconnect the equipment.
Users should ensure for their own protection that the ground connections
of the power utility, telephone lines and internal metallic water pipe sys-
tem, are connected together. This protection may be particularly impor-
tant in rural areas.
1.6 SERVICE INFORMATION
All warranty and non-warranty repairs must be returned freight prepaid
and insured to Patton Electronics. All returns must have a Return Mate-
rials Authorization number on the outside of the shipping container. This
number may be obtained from Patton Electronics Technical Support at:
tel: [phone]
email: suppor[email protected]
www: http://www.patton.com
Note Packages received without an RMA number will not be
accepted.
Patton Electronics' technical staff is also available to answer any ques-
tions that might arise concerning the installation or use of your Patton
Model 2710. Technical Services hours: 8AM to 5PM EST, Monday
through Friday.
Users should not attempt to make such connections them-
selves, but should contact the appropriate electric inspec-
tion authority, or electrician, as appropriate.
CAUTION

8
2.0 GENERAL INFORMATION
Thank you for purchasing this Patton Electronics product. This product
has been thoroughly inspected and tested and is warranted for One Year
parts and labor. If any questions arise during installation or use of the
unit, contact Patton Electronics Technical Services at [phone].
2.1 FEATURES
• Terminates T1/FT1 Circuits over a 4-Wire RJ-48C interface
• Connects to standard CPE Serial Interfaces
• Common Framed nx56/64 rates up to 1.536 Mbps
• Unstructured Rates at 1.544 Mbps
• D4 or ESF Framing Modes
• Supports AMI or B8ZS/B7ZS Line Coding
• ConÞguration via Software Control Port or Internal DIP Switches
• Seven Easy-to-Read LED Indicators Monitor Data & Diagnostics
• Internal, External or Receive Recover Clocking
• Also Operates as a High-Speed Point-to-Point Modem
• Compact Size Plugs Directly into a Router, Switch or other DTE
• Made in USA
2.2 DESCRIPTION
The NetLink-T1™ Model 2710 Series are single port T1/FT1 CSU/DSUs
that provide high-speed WAN connectivity in an ultra-compact housing.
Plugging directly into the V.35 WAN port of a switch, router or multiplexer,
the NetLink-T1™ provides T1 or FT1 access at connection at data rates
of 1.544 Mbps, nx64, and nx56 (n=1 to 24 channels). The Netlink-T1™
is an excellent choice when terminating leased line services, Frame
Relay backbones, internet access as well as LAN-to-LAN services.
The Netlink-T1™ provides digital access to a local WAN service provider
or directly between two facilities over a dedicated 4-Wire circuit. LAN
bandwidth, framing and coding options are programmed via internally
accessible DIP switches or via a rear-mounted EIA-232 control port. The
Netlink-T1™ supports D4/ESF framing options and AMI/B8ZS/B7ZS line
coding. Netlink-T1™ also supports a full range of system and diagnostic
features that make system setup easy.

9
The NetLink-T1™ provides T1 terminations over a modular RJ-48C jack
and comply with jitter tolerance capabilities as speciÞed in ANSI T1.403
and AT&T TR62411. External power options include 120VAC and Uni-
versal Interface 100-240VAC.
2.3 SUPPORTED APPLICATIONS
The NetLink-T1™ CSU/DSU provides a T1 (DS1) network termination
between the service provider and customer premises equipment (CPE)
such as a router. The Netlink-T1™ can also be used as a high-speed
short haul modem for campus applications.
The 2710 as the Interface between the Telco and CPE
The NetLink-T1™ provides the interface between the service provider
and customer equipment, such as a router or switch (See below).
The 2710 as a High-Speed Short Range Modem
The NetLink-T1™ can also be installed into high-speed campus applica-
tions. In this application, a pair of NetLink-T1™ units operate as short
range modems (See below).
T1
Network
Model 2710
1.544Mbps
or nx56/64
Router
LAN
RXD LOS ALM
ERR
T/L PWR TXD
Model 2700
RXD LOS ALM
ERR
T/L PWR TXD
Model 2700
NetLink-T1“
Model 2710s
1.544MBps
or nx56/64
Up to 6000 Feet
(1.83 km)

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3.0 CONFIGURATION
The Model 2710 features conÞguration capability via hardware switches
or a software control port. This section describes all possible hardware
and software switch conÞgurations of the NetLink-T1™.
3.1 DIP SWITCH CONFIGURATION
The Model 2710 has eight internal DIP switches that allow conÞguration
for a wide range of applications. The eight switches are accessed by
opening the plastic case with a small screwdriver. Figure 1 (below)
shows the location of the DIP switches on the bottom of the printed cir-
cuit board.
Figure 1. Model 2710 Series bottom view, showing location of DIP switches
The Model 2710 DIP switches (Switches SW1 - SW8) can be conÞgured
as either “On” or “Off”. Figure 2 (below) shows the orientation of the DIP
switches with respect to ON/OFF positions.
Figure 2. Close up of DIP switches showing ON/OFF positions.
ON
12345678
Software Configuration Port
ON
OFF
DIP Switches
12345678
ON
ON
OFF

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Default positions for Switches SW1-SW8 are shown in the table on the
following page. Descriptions of each switch follow the table.
Switches SW1, SW2, and SW3
Use Switches SW1, SW2 and SW3 to set the DTE data rate. Each set-
ting represents an nx56/nx64 setting.
Switch SW4: Line Framing and Coding
Use Switch SW4 to control the Network Line Framing and Coding
Options. Set these options to be the same as the Line Framing and Cod-
ing Options given to you by your Service Provider. If you are using two
Model 2710s together as short range modems, set both units identically.
SWITCH SET SUMMARY TABLE
Position Function Factory Default Selected
Option
SW1
SW2
SW3
Data Rate
Data Rate
Data Rate
On
On
On
1.536 Mbps
(DTE Rate)
SW4 Framing & Coding Off ESF/B8ZS
SW5 DS Zero Rate On 64 kbps
SW6 Clock Mode Off Network
SW7
SW8
Line Build Out
Line Build Out
Off
Off 0dB
SW1 SW2 SW3 Speed
OFF OFF OFF Clear Channel (Unframed)
ON OFF OFF 112kbps/128kbps
OFF ON OFF 224kbps/256kbps
ON ON OFF 336kbps/384kbps
OFF OFF ON 448kbps/512kbps
ON OFF ON 672kbps/768kbps
OFF ON ON 896kbps/1024kbps
ON ON ON 1344kbps/1536kbps
SW4 Line Framing & Coding
ON ESF/B8ZS
OFF D4/AMI

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Line Framing Options:
• D4/Superframe: The D4 framing format, as speciÞed in AT&T
TR62411 is the standard in which twelve frames make up a super-
frame. All signaling and synchronization are done in-band.
• Extended Superframe: Extended Superframe, as speciÞed in AT&T
TR 54016, consists of twenty-four (24) T1 frames. The framing bits are
now used for framing, CRC and the Facility Data Link (FDL). The FDL
allows maintenance messages and information to be passed between
the 2710 and the Central OfÞce.
Line Coding Options:
• Alternate Mark Inversion (AMI): This mode does not inherently
account for ones density. To meet this requirement, each time slot can
be reduced to 56 kbps and the Least SigniÞcant Bit (LSB) of each time
slot set to one.
• Bipolar 8 Zero Substitution (B8ZS): This mode assures proper bit
density in the data stream. In this mode any data pattern can be trans-
mitted without causing ones density errors. This mode allows for 64
kbps clear channel timeslots.
Switch SW5: DS0 Channel Rate
Use Switch SW5 to set the DS0 rate.
Switch SW6: Clock Mode
Set Switch SW6 to determine the 2710’s transmitter timing.
Note When using the Model 2710 as a high-speed short range
modem, one unit of the link must be conÞgured in Internal Clock
mode, and the opposite end unit must be conÞgured for Network
Clock mode.
SW5 Setting
OFF 56 kbps
ON 64 kbps
SW6 Clock Mode
OFF
Network Clock. Transmitter timing is derived from the
received line signal.
ON
Internal Clock. Transmitter clock is derived from an internal
oscillator.

13
Switches SW7 and SW8: Line Build Out
Use Switches SW7 and SW8 to set the Line Build Out (LBO). The Line
Build Out varies the pulse shape and attenuation of the signal sent to the
network. The amount of Line Build Out depends on NetLink™ T1’s dis-
tance to the last repeater. The telephone company providing the service
will advise on the amount of LBO necessary.
SW6 SW7 Function
OFF OFF 0-133 ft (0dB)
ON OFF -7.5dB
OFF ON -15.0dB
ON ON -22.5dB

14
3.2 SOFTWARE CONFIGURATION
The NetLink-T1™ features a menu-driven command system that allows
you to monitor/conÞgure its operating parameters. Follow the instruc-
tions below to conÞgure the Model 2710 using the software switches:
1. Plug the 9-pin male end of the cable to your terminal or computer’s
DB-9 serial port and start up the terminal emulator software if nec-
essary. Plug the miniature stereo plug into the rear of the unit. The
small recessed jack on the right side of the unit is the control port
jack.
Note If your terminal uses a DB-25 connector, please use a DB-9 to
DB-25 Adapter to connect to the cable (See Model 18PC-M).
2. Power up the terminal and set its RS-232 port as follows:
9600 Baud
8 data bits, 1 stop bit, no parity
Local echo off
ANSI or VT-100 emulation
3. Here is an example of a terminal emulator setup session. In normal
font are the various parameter types. In bold type are the values that
should be used for best results.Your terminal program’s setup
screen may differ from this one:
4. When the unit is Þrst turned on, the terminal screen may appear
blank. Press the <Enter> key. If your serial connection is good, then
the unit will immediately display a password prompt.
5. Type in the password and press <Enter>. The factory default pass-
word for the unit is:
patton .
Note If the entry is incorrect, the password screen will clear and
prompt you again for the correct password.The password you
Baud Rate:
9600
Parity:
None
Data Length:
8
Stop Bits:
1
Default terminal type: VT100
Local Echo: OFF
Add Line Feeds after CRs: OFF
Received Backspace Destructive: ON
Backspace key sends: BS
XON/XOFF software ßow control: ON
CTS/RTS hardware ßow control: OFF
DSR/DTR hardware ßow control: OFF

15
enter will not be shown. For security, asterisks will be displayed
for each letter you type. The maximum length of the password,
which can include any character the terminal can generate, is 16
characters.
6. The NetLink-T1™ will then display the Main Menu screen.
Introduction to Main Menu
After entering the password, you may access all of the system’s func-
tions and parameters. The Main Menu looks like this:
1. To make a selection, key the highlighted letter that corresponds to a
menu selection.
2. To execute the selection, type <Enter/CR>
3. Select Save Changes from Main Menu after making modiÞca-
tions to any NetLink-T1™ parameter. Otherwise, changes will be
lost when the NetLink-T1™ is turned off.
The Main Menu options are brießy described below:
System ConÞguration options allow you to change various
aspects of the NetLink-T1™’s operation, e.g., framing, line cod-
ing, and aggregate bandwidth.
System Diagnostics/Statistics options allow you to monitor the
network performance, initiate V.54 loops, local loops, and send
test patterns. Network performance parameters are updated
once a second, giving you the ability to quickly determine if there
is a problem.

16
System ConÞguration
The default System ConÞguration menu looks like this:
The System ConÞguration options are described below:
– Line Format: ESF
(default)
Options: ESF, D4, UNFRAMED
D4: This is an older, but widely used, line format that does not pro-
vide FDL, so network interface performance cannot be monitored so
easily. AT&T TR 62411 contains the speciÞcations for this format
and the ESF. D4 is also known as Superframe format. According to
TR 62411, “The Superframe format…consists of 12 frames of 193
bits each for a total of 2316 bits. Each 193 bit frame consists of 192
bits preceded by one framing bit….the framing bit is time shared to
Unit Options allow you to customize the NetLink-T1™ for your
location.You can change the default header names to give each
unit a unique name and password. Also, you can reset the unit to
its default settings without the manual. It also has a Service Infor-
mation screen in case you need technical assistance from Pat-
ton.
Save Changes Once you have conÞgured the unit to your satis-
faction, you can save the changes permanently by executing the
Save Changes command. This will update the unit’s conÞguration
and save all the parameters to permanent memory.
Logoff For security, log off the control menu by executing the
Logoff command. This will blank the screen until an [Enter] key is
pressed.

17
both synchronize the terminal equipment and to identify the signal-
ing frames.” (Sec. 4.1.1)
ESF: This stands for Extended Superframe Format, a line format
developed by AT&T. AT&T Technical Reference 54016 (TR 54016)
deÞnes the ESF, a format which is commonly used to allow monitor-
ing of the network interface performance over the Facility Data Link
(FDL). AT&T TR 62411 says, “the Extended Superframe Format
“extends” the DS1 superframe structure from 12 to 24 frames…for a
total of 4632 bits. It redeÞnes the 8 kb/s channel previously used
exclusively for terminal and robbed bit signaling synchronization.”
The ESF provides a 4 kb/s data link, called the FDL, which allows for
in-service monitoring and fast troubleshooting. Certain network ser-
vices require the ESF.
UNFRAMED: This is a special mode that allows you to achieve the
maximum possible data rate of 1.544 Mb/s (million bits per second)
by using the framing bits for data transmission.There is no signaling
or FDL. This is commonly used for campus connections, and by the
Federal government and the military. This format is not to be used
when connecting to a public carrier’s network without its permission.
This provides one channel at a rate of 1.544 Mb/s. In addition, this
format can be used with external clocking.
– Line Coding: B8ZS
(default)
Options: AMI, B8ZS, B7ZS.
AMI: Alternate Mark Inversion deÞnes a pulse as a “mark”, a binary
one, as opposed to a zero. In a T1 (DS1) network connection, sig-
nals are transmitted as a sequence of ones and zeros. Ones are
sent as pulses, and zeros are sent as spaces, i.e., no pulse. Every
other pulse is inverted from the previous pulse in polarity, so that the
signal can be effectively transmitted. This means, however, that a
long sequence of zeros in the data stream will cause problems,
since the CSU/DSU receiving the signal relies on the signal to
recover the 1.544 Mb/s clock. To get around this problem, one
method is to limit the data rate per channel (known as a DS0,
because it is a 64 kb/s portion of the DS1 frame or superframe) to
56 kb/s and forcing a pulse in the last data bit to ensure a minimum
pulse density in the signal. If you must use AMI with a DS0 data rate
of 64 kb/s, you should ensure that the data terminal equipment con-
nected to the unit provides a minimally acceptable pulse density. For
this reason, there are advantages to using B8ZS instead.

18
B8ZS: Bipolar violations occur when consecutive pulses are of the
same polarity. In B8ZS, or Bipolar Eight Zero Substitution, bipolar
violations are introduced deliberately to indicate that eight zeros
have been transmitted. This special encoding is recognized by the
receiver and decoded correctly. See AT&T TR62411 Section 4.2.2
for a detailed description of B8ZS. This enables information to be
sent over a T1 connection without any constraints on the data’s
pulse density.This is the most acceptable way to accomplish 64 kb/s
on each DS0 channel.
B7ZS: This stands for Bipolar Seven Zero Substitution. Instead of
introducing bipolar violations, this method substitutes a one for a
zero in bit 7 (out of 8) of a DS0 channel when the data in that chan-
nel are all zeros.This is a special form of AMI and is compatible only
with special equipment. For most applications, AMI or B8ZS will suf-
Þce..
– DS0 Line Rate: 64kbps
(default)
Options: 64kbps, 56kbps.
64kbps: Also known as Clear Channel, this takes full advantage of
the available bandwidth in a DS0 channel. Implementing it usually
requires B8ZS line coding. In certain cases, special equipment may
implement Clear Channel using AMI or B7ZS. Consult the equip-
ment manual for compatibility.Your carrier will advise you on
whether to use 64 or 56 kb/s. Campus applications may not have
such restrictions, enabling you to use 64kbps. In Unframed format,
the 24 DS0s and the framing bits are combined to provide 1.544Mb/
s for your use.
56kbps: This uses only the Þrst seven bits of the DS0, limiting the
data rate per DS0 channel to 56 kb/s.Your carrier will advise you on
whether to use 64 or 56 kb/s. This is not available when using the
Unframed format.

19
– Clocking: Network
(default)
Options: Network, Internal, External
Network: This is the most commonly used setting when connect
ing to a carrier’s network. In this mode, the unit recovers the clock
from the received signal and uses it to transmit data. In this way the
unit remains synchronized to a master clock. In campus applica-
tions, one of the units must be set to Internal clock, and the other
end is set to Network clock. At all times, there must be only one
clock source. Otherwise, clock slips and framing errors and bit errors
may occur.
Internal: This is commonly used in campus applications, where the
unit is not connected to the public telephone network directly. In this
mode, the unit uses the on-board oscillator as the transmit clock
source.
External: This is a special mode that should only be used with the
Unframed format. In this mode, the unit requires a 1.544 Mhz clock
signal from the DTE via the external clock pin on the DTE interface
connector. Most applications will use Network or Internal clock
modes.
– Line Build Out (dB): 0-133 feet, 0 dB (default)
Options: 0 – 133 feet, 0 dB
133 – 266 feet
266 – 399 feet
399 – 533 feet
533 - 655 feet
-7.5 dB
-15.0 dB
-22.5 dB
This controls the transmitter signal strength and pulse shape. For most
applications, the default setting will sufÞce. When connecting to a carrier
connection, the carrier will determine what LBO is necessary. 0 dB pro-
vides the highest signal strength and therefore the longest distance,
while –15.0 dB provides the lowest usable signal strength. The last set-
ting, –22.5 dB, is usually only used to test the line and should not be
used in normal applications.

20
– ESF Data Link: ANSI T1.403 (default)
Options: ANSI T1.403, AT&T TR54016
ANSI T1.403: This ANSI developed standard (see ANSI T1.403-
1995: Network-to-Customer Installation—DS1 Metallic Interface)
uses the FDL to send and receive one second Performance Report
Messages (PRMs). The messages contain the NI performance over
the last four seconds. Thus, up to three consecutive messages may
be lost without loss of information. It is available only with ESF.
When ANSI T1.403 is selected, requests to send AT&T performance
reports (ref. AT&T TR 54016) are ignored
AT&T TR54016: Developed by AT&T, this FDL method differs princi-
pally from the ANSI method in two ways: First, the ANSI method
transmits messages continuously, whereas the AT&T method trans-
mits a performance report only upon a request from the remote end
for a report. Second, the AT&T method provides a historical sum-
mary, up to the last 24 hours, of NI performance. Only the service
provider or special test equipment can send these requests. When
AT&T TR54016 is selected, ANSI PRMs are still transmitted by the
unit, but only PRMs sent by the carrier will be recognized.To receive
PRMs from another customer unit (i.e., in a campus application),
select ANSI T1.403. When the frame is not ESF, the FDL is disabled.
– ESF Carrier Loops: Enabled (default)
Options: Enabled, Disabled
The ESF format provides the CO the ability to put the customer installa-
tion’s NetLink-T1™ into loopback mode. The NetLink-T1™ recognizes
these special messages that are sent over the FDL. When enabled, the
unit will respond to these loopback commands and go into or out of loop-
back mode. When disabled, the unit will not respond, although it still rec-
ognizes the loopback commands. When in loopback, the unit will remain
in loopback until a loopback exit command is received or when the loop-
back timer times out. See “Unit Options” on page 29 to make Loop Time-
out choices. This feature allows the remote user to regain control should
one be locked out after a loopback is initiated.