Spirent DLS 6700 User manual

P/N 7104000557
User Guide
DLS 6700
Operating Manual
Version 1.02
Nov 2004

Spirent Communications, Inc.
Spirent Communications
750 Palladium Drive
Ottawa, Ontario, Canada
K2V 1C7
Support Contacts
Canada
E-mail: [email protected]
Web: http://ae.spirentcom.com
Toll Free: 1-800-465-1796
Phone: + 1 : 613-592-7301
Fax: [phone]
Europe
E-mail: [e-mail]
Web: http://support.spirentcom.com
Phone: [phone]
Fax: [phone]

DLS 6700 Operating Manual
Spirent Communications 7104000557 Page i
Table of Contents
1. INTRODUCTION ......................................................... 1-1
1.1 About Spirent’s Involvement in Wireline Simulation ........... 1-1
1.2 About the DLS 6700 ADSL2++ Wireline Simulator ............ 1-1
1.3 About this Manual ......................................................... 1-2
2. GETTING STARTED .................................................... 2-1
2.1 Receiving and Unpacking the Unit ................................... 2-1
2.2 Setup Overview ............................................................ 2-1
2.3 Cabling Requirements ................................................... 2-1
2.4 Front Panel Indicators ................................................... 2-2
2.4.1 Reading Remote and Power Status ............................ 2-2
2.5 Rear Panel Connections ................................................. 2-2
2.5.1 Connecting to Power ................................................ 2-3
2.5.2 Connecting to Analog Devices with RJ-11 Connectors ... 2-3
2.6 DLS 6700 Remote Control ............................................. 2-4
2.6.1 Connecting the Computer via the Serial Port (RS-232) .2-4
3. DLS 6700 SOFTWARE ................................................ 3-1
3.1 DLS 6700 Software ....................................................... 3-1
3.1.1 Installation ............................................................. 3-1
3.1.2 Starting the DLS 6700 Software ................................ 3-1
3.2 Communications Interface Selection ............................... 3-2
3.2.1 Identify Chassis ...................................................... 3-2
3.2.2 Start Online ............................................................ 3-2
3.2.3 Start Offline ........................................................... 3-2
3.3 Main Editing Grid .......................................................... 3-2
3.3.1 Controlling the Line ................................................ 3-2
3.3.2 Groups .................................................................. 3-3
3.4 Menu Selections ........................................................... 3-4
3.4.1 File ....................................................................... 3-4
3.4.2 Tools ..................................................................... 3-4
3.4.3 About .................................................................... 3-4
4. REMOTE CONTROL ..................................................... 4-1
4.1 RS-232 Serial Interface ................................................. 4-1
4.1.1 Message Terminators ............................................... 4-1
4.1.2 Example using the RS–232 Interface ......................... 4-2
4.2 Data Formats ............................................................... 4-2
4.3 Command Syntax ......................................................... 4-3
4.4 Device Dependent Commands ........................................ 4-3
4.4.1 :SETting:CHANnel:LINE <Line Number>,<Length> ..... 4-4
4.4.2 :SYStem:Communicate:serial:echo <Off|On> ............. 4-4
4.4.3 :SYStem:COMMunicate:SERial:PACE <pace> .............. 4-5
4.5 Common Command Set ................................................ 4-5
4.6 Status Reporting .......................................................... 4-9
4.6.1 Status Byte Register (STB) ....................................... 4-9
4.6.2 Event Status Register (ESR) ....................................4-10
4.6.3 DLS 6700 Synchronization .......................................4-11
5. TROUBLESHOOTING .................................................. 5-1

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6. REFERENCES ............................................................... 6-1
7. CUSTOMER SUPPORT ................................................ 7-1
7.1 Customer Service Contact Information ............................ 7-1
7.2 Protecting Your Investment ............................................ 7-1
7.3 Extended Warranty ....................................................... 7-1
7.4 Three-Year Calibration Agreement ................................... 7-2
8. WARRANTY .................................................................. 8-1
9. SHIPPING THE UNIT ................................................. 9-1
10. SPECIFICATIONS ....................................................10-1
10.1 General ....................................................................10-1
10.2 Environmental ...........................................................10-1
10.3 Mechanical ................................................................10-1
10.4 Carton Contents: .......................................................10-2
11. SAFETY ......................................................................11-1
11.1 Information ..............................................................11-1
11.1.1 Protective Isolation ...............................................11-1
11.1.2 Before Operating the Unit ......................................11-1
11.1.3 Power Supply Requirements ...................................11-1
11.1.4 Fuse Configuration ................................................11-1
11.1.5 Connections to a Power Supply ...............................11-1
11.1.6 Operating Environment .........................................11-1
11.1.7 Class of Equipment ...............................................11-2
11.2 Instructions ..............................................................11-2
11.2.1 Before Operating the Unit ......................................11-2
11.2.2 Operating the Unit ................................................11-2
11.3 Symbols ...................................................................11-2
APPENDIX A. MEASUREMENTS AND TEST RESULTS A-1
A.1 Measurement of the DLS 6700 ....................................... A-1
A.2 Common Errors ............................................................ A-2
A.3 Typical Attenuation Characteristics .................................. A-2
APPENDIX B. BACKGROUND NOISE MEASUREMENTS B-1

DLS 6700 Operating Manual
Spirent Communications 7104000557 Page 1-1
1. INTRODUCTION
1.1 About Spirent’s Involvement in Wireline Simulation
Thank you for choosing Spirent Communications.
The DLS 6700 ADSL2++ Multi-line Production Wireline Simulator has been designed
to meet the needs of very high volume manufacturers of ADSL2++ bandwidth access
products (DC to 4.5 MHz). The DLS 6700 is used to ensure xDSL copper access prod-
ucts perform correctly before they leave the production floor. The DLS 6700 achieves
a low cost per port by offering 8, 12 or 18 port configurations in a 1 U rack mountable
chassis.
1.2 About the DLS 6700 ADSL2++ Wireline Simulator
The DLS 6700 ADSL2++ Multi-line Production Wireline Simulator simulates the inser-
tion and return loss of a twisted copper cable, sometimes called a wireline.
The “DLS 6700 Series” currently includes the DLS 6726 (26AWG), and will be referred
to as the “DLS 6700” within this document. Specifications for the DLS 6726 have
been derived from North American (ANSI) standards.
Figure 1.1 DLS 6700 ADSL2++ Multi-line Production Wireline Simulator
The DLS 6700 ADSL2++ Wireline Simulator simulates 26 AWG cable for ADSL2++/
ADSL2+/ADSL2/ADSL production and verification testing. It has a reach of up to 24
kft in 1,000 ft increments, and a bandwidth of DC to 4.5 MHz. The unit is fully bi-
directional, with all cable characteristics being accurately simulated using passive
components.
The DLS 6700 can simulate up to 18 wirelines per unit. The simulated wireline
lengths are controlled remotely via an RS-232 port.
There are two software methods for controlling the wireline simulator: you can use
the GUI which ships with the DLS 6700, or you can write custom, script-based soft-
ware to operate your DLS 6700-based test system.
The DLS 6700 Software configures and controls the DLS 6700 ADSL2++ Wireline
Simulator remotely through the RS-232 interface. This software runs on any
WindowsTM 98, NT 4.0 with service pack 4.0 and up, or WindowsTM 2000 compatible
computer.
One or more wireline simulators can be integrated into a larger test system, limited
by the number of COM ports available on the controlling computer. The configuration
software that ships with the DLS 6700 can access up to 16 com ports.
Figure 1.2 illustrates an example of a typical test setup using the DLS 6700 ADSL2++
Wireline Simulator.

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Page 1-2 7104000557 Spirent Communications
Figure 1.2 Example Test System Setup
1.3 About this Manual
Read Chapter 2 "GETTING STARTED" thoroughly before powering up the DLS 6700
ADSL2++ Wireline Simulator.
This manual provides information about the various aspects of the wireline simulator,
such as loop configurations, remote control, warranty, specifications and contact
information.
The configuration software that ships with the DLS 6700 provides you with full control
over the characteristics of each DLS 6700 simulated loop.
We recommend that you develop your own scripts based on the type of automated
testing that best suits your products.
The common and device specific commands sets used to control the DLS 6700 are
fully explained in Chapter 4 "REMOTE CONTROL".
If you have any questions after reading this manual, please contact your Spirent
Communications sales representative or a member of the Customer Service team.
Please find contact information in Chapter 7 "CUSTOMER SUPPORT" of this manual.

DLS 6700 Operating Manual
Spirent Communications 7104000557 Page 2-1
2. GETTING STARTED
This chapter provides basic instructions on the setup of a DLS 6700 ADSL2++ Wire-
line Simulator.
2.1 Receiving and Unpacking the Unit
Each DLS 6700 chassis has been shipped in a reinforced shipping container. Please
retain this container in case you need to ship the wireline simulator to another loca-
tion or for repair. The DLS 6700 system contains the following:
• DLS 6700 Series chassis
• 1 AC to DC wall plug-in adapter
• 1 RS–232C inter-connection cable
• 1 DLS 6700 CD (software and related documents)
• 1 Operating Manual on CD
Check that you have received all the items on the list and report any discrepancies to
Spirent Communications. See Chapter 9 "SHIPPING THE UNIT" for information.
2.2 Setup Overview
To test:
1) Connect the power cord on the back of the DLS 6700 chassis and switch the
power on.
2) Connect the serial cable from the control computer to the back of the
DLS 6700.
3) Connect digital subscriber line access multiplexer (DSLAM) equipment to one
of the “Output” ports at the back of the DLS 6700.
4) Connect customer premise equipment (CPE) equipment to the corresponding
“Input” port at the back of the DLS 6700.
5) Start the DLS 6700 Software.
6) Connect the control software to the DLS 6700. From the list of available serial
ports on your computer (listed in the “Interfaces and Identification” panel of
the main window), choose the one attached to the DLS 6700 you want to con-
trol. Press the Start Online button. This will open the DLS 6700 control win-
dow, allowing you to adjust the length of each wire line.
7) Adjust the line lengths for the test loops.
8) Begin testing.
See the following sections for detailed information.
2.3 Cabling Requirements
Cabling, switches and other equipment are needed to connect the DSLAM, the loop
simulator, and the CPE. Cables should be kept as short as possible so minimum noise
is coupled into the cables. Recommended cables are the CAT5 UTP. Since the length is
typically short (e.g., 2 feet), this does not affect measurements.
Computer screen and power supplies radiate in ADSL frequency bands. This noise
may be generated by either internal or external power supplies. When the noise levels

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Page 2-2 7104000557 Spirent Communications
are greater than -140 dBm /Hz, they will limit the ADSL2++ performance and influ-
ence the test results. These devices should be placed at a distance from the test setup
or even switched off.
The interconnection wiring for the “Output” and “Input” Ports should be physically
separated as crosstalk can occur between cabling. Configure the cables so that they
are not touching and the cable connecting to the DSLAM and CPE are separated as
much as possible (at least 15 cm).
2.4 Front Panel Indicators
The DLS 6700 chassis has 2 LEDs which indicate the power and remote status.
The Power LED indicates when the unit is on, and doubles as an error status indica-
tor.
The Remote LED indicates when the DLS 6700 has received a command from the
control computer.
Figure 2.1 DLS 6700 Front Panel
2.4.1 Reading Remote and Power Status
The POWER LED turns green when the power is turned on. The power LED blinks red
if it fails its self-test, or solid red if it detects an internal error.
The REMOTE LED is off after a power-up or a reset. When the unit receives the first
remote message, the REMOTE LED turns green if the command is valid or turns red if
an error is detected. An invalid command or an out-of-range value will cause an error.
The REMOTE LED stays red until the error flags are cleared (see the command *ESR?
for more details). When the REMOTE LED is red, the unit can still communicate as
normal, but you should investigate why the error occurred. Chapter 4 "REMOTE CON-
TROL" shows examples on how to read the ESR register, clear the error flags and
make the REMOTE LED green once error conditions have been resolved.
2.5 Rear Panel Connections
All connectors for the DLS 6700 are located on the rear panel (see Figure 2.2 "DLS
6700 Back Panel")
S I T .
DLS 6700 ADSL2++
Multiline Production Wireline Simulator
spirentcom.com
POWER REMOTE

Chapter 2: GETTING STARTED
Spirent Communications 7104000557 Page 2-3
Figure 2.2 DLS 6700 Back Panel
1) Power Input: Connect to an AC wall adapter power source
2) RS–232 (DCE) Serial Connector: Connect to a computer for remote control
3) RJ - 11 “Output” : (8, 12 or 18, depending on model) Connect to DUT (usu-
ally DSLAM devices).
4) Ground Connection: Connect to earth ground (optional)
5) RJ - 11 “Input”: (8, 12 or 18, depending on model) Connect to DUT (usually
CPE modems).
2.5.1 Connecting to Power
Connect the unit via the wall plug-in adapter (provided with the unit) at the back of
the unit to an AC power supply appropriate for your specific country. Please see Chap-
ter 10 "SPECIFICATIONS" for more details.
The power LED will turn on when the power is connected.
WARNING Before operating the unit, please refer to Section 11.1.5 "Connections
to a Power Supply", to ensure that the correct AC/DC adapter is used.
NOTE
Please refer to Chapter 11 "SAFETY" for more details.
2.5.2 Connecting to Analog Devices with RJ-11 Connectors
In a typical setup the Telephone Exchange (Central Office) equipment would be con-
nected to an “Output” Port, and the customer site equipment to the corresponding
“Input” Port of the DLS 6700 wireline simulator. The pinout of the RJ-11 female con-
nector is shown in Figure 2.3.
9
18
1
10
INPUT
OUTPUT
DB-25
Power
500 mA Max
12V DC
1
9
10
18
12345

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Page 2-4 7104000557 Spirent Communications
Figure 2.3 RJ-11 Female Connector
The two center pins of the RJ-11 connector (pin 2, Tip; and pin 3, Ring) carry the
signal.
These connections are balanced. We recommend that these leads be shorter than 60
cm if you are using frequencies up to 4.5MHz. It is possible to use longer leads as the
frequency decreases.
WARNING The maximum input to any DLS 6700 port must not exceed +/-100 V
or 100 mA between Tip and Ring. Exceeding these limits could damage
the unit.
2.6 DLS 6700 Remote Control
The DLS 6700 ADSL2++ Wireline Simulator is configured through its RS-232 serial
port. The reach (length) of each simulated wireline can be adjusted remotely using
configuration software.
You can use the included Spirent Communications’s GUI to configure the DLS 6700;
or you can develop your own custom configuration software using the DLS 6700 com-
mand set. This command set is covered in this manual (see Chapter 4 "REMOTE
CONTROL"), to assist you in developing custom software and scripts.
2.6.1 Connecting the Computer via the Serial Port (RS-232)
Connect one end of an RS-232 serial cable to the RS-232 connector located on the
back panel of the DLS 6700 chassis and the other end to a serial COM port connector
on the computer.
The DLS 6700 GUI supports up to 16 COM ports. It will automatically detect all serial
ports available on the control computer between COM1 and COM16. Only available
COM ports will be listed in the “Interfaces and Identification” panel of the main GUI
window. COM ports that exist on the control PC but are already open will not appear
in this list.
Balanced
Connection
Pin 2 Pin 3

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Spirent Communications 7104000557 Page 3-1
3. DLS 6700 SOFTWARE
3.1 DLS 6700 Software
The DLS 6700 GUI provides you with an interactive interface to control the DLS 6700.
NOTE
This software runs on any WindowsTM 98, NT 4.0 with service pack 4.0
and up, or WindowsTM 2000 compatible computer.
3.1.1 Installation
To install the software, run SETUP.EXE from the installation CD if it does not start au-
tomatically when the CD is inserted. The user is prompted to specify the directory
where the software should be installed.
3.1.2 Starting the DLS 6700 Software
To start the DLS 6700 Control Software, click on the Start button in Windows, select
“Programs > Spirent Communications > DLS 6700”. The program will start and display
this screen:
Figure 3.1 DLS 6700 Control Software

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3.2 Communications Interface Selection
The DLS 6700 Control Software allows the user to specify a communications interface
for each DLS 6700 chassis to be controlled. Select the appropriate option button for
the desired COM port.
The DLS 6700 Control Software allows the user to choose the COM port which will be
used to control the DLS 6700. Select the COM port using the list box.
NOTE
The “Interfaces and Identification” panel lists only available COM ports.
If you wish to run multiple sessions of the GUI, you need to launch all
the sessions first before going online with any of the DLS 6700 units.
3.2.1 Identify Chassis
You can correlate which DLS 6700 chassis is attached to which COM port using the
“Identify Chassis” button.
Select a COM port from the “Interfaces and Identification” panel, and press the “Iden-
tify Chassis” button. The GUI will then attempt to flash the Remote LED on the DLS
6700 unit using the selected COM port. During the identification, the “Stop Identifica-
tion” button will appear, and all the other buttons will be disabled until the “Stop Iden-
tification” button is clicked.
3.2.2 Start Online
Once the correct COM Port is selected, click Start Online to use the program to control
your DLS 6700.
3.2.3 Start Offline
Click on “Start Offline” to start the program without controlling a DLS 6700 unit. This
is useful for viewing the features of the program where a DLS 6700 unit is not available.
3.3 Main Editing Grid
When the program starts, unless Start Offline is selected, the DLS 6700 Control Soft-
ware reads the DLS 6700 on the specified interfaces to find out which lines are installed
in the unit. The software will determine the gauge, current length, minimum, maxi-
mum, and increment lengths, and present the information on the screen.
The appearance of the Main Editing Grid will depend on what lines are installed in your
DLS 6700 unit. The range and the gauge of the line may be different from that shown
in the diagram.
3.3.1 Controlling the Line
The most direct way to control a DLS 6700 unit is to click on the Spin controls (up and
down arrows) to change the length of the line. This will “step” the length by the appro-
priate increment or decrement. Values can also be entered in the Type In entry boxes.

Chapter 3: DLS 6700 SOFTWARE
Spirent Communications 7104000557 Page 3-3
Regardless of the method chosen, the program will ensure that the final value is within
the range of the line and will round to the nearest correct step size.
3.3.2 Groups
The Grouping feature is a convenient way to set many lines at once. Select the lines
to be modified and then apply a length to the grouped lines.
Figure 3.2 DLS 6700 Main Editing Grid
To specify which lines are in the group, click the checkbox in the Grouped column for
each line that is to be grouped. Use the “Select All” and “Deselect All” buttons to set
and clear ALL the check boxes. Another button, Invert Selection, exchanges the
checked and cleared check boxes.

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Page 3-4 7104000557 Spirent Communications
Once the lines are selected, the length can be changed with either the Type-In box or
the Spin control. Click on the “Apply Length to Grouped Lines” button to send the
length to each of the selected lines.
NOTE
The length setting for the group length only gets applied when 'Apply
Length to Grouped Lines' is pressed, whereas the individual line length
is applied as soon as the value is changed.
3.4 Menu Selections
3.4.1 File
Load - Retrieves a previously stored file of DLS 6700 settings from disk.
Save - Stores the current settings of the DLS 6700 to a file on disk
Exit - Shuts down the program
3.4.2 Tools
Identify Units - Flashes the Remote LED on the appropriate unit. When Identify Unit is
clicked, the “Stop Identification” button will appear and it must be clicked before the
user can do anything else.
3.4.3 About
Shows information on the program such as version number.

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Spirent Communications 7104000557 Page 4-1
4. REMOTE CONTROL
The DLS 6700 is controlled via the RS-232 (serial) interface, allowing the integration
of the DLS 6700 into a larger test system. The DLS 6700 remote control is designed
with several standards in mind:
• The Common Commands follow IEEE 488.2.
• The Device Dependent Commands (see Section 4.4 "Device Dependent Com-
mands") are based upon the Standard Commands for Programmable Interfaces
(SCPI).
• The serial port physical interface follows the EIA RS-232 standard.
4.1 RS-232 Serial Interface
The DLS 6700 uses a female DB-25 or an RJ-45 connector, and is configured as a DCE
device. It can therefore be connected directly to a PC serial port.
The RS-232 standard is equivalent to the European V.24/V.28 standards. In this man-
ual we use the term RS-232 to refer to both of these two standards. Generally, the
computer literature will use the words “serial”, “COM1” and “COM2” to refer to the
RS-232 interface. Note that the DLS 6700 cannot use the parallel port of a computer
(the female connector).
To use the RS-232 interface, connect your computer to the DLS 6700 and set the
computer to 9600 bps baud rate, no parity, 8 data bits per character, 1 stop bit and
RTS/CTS hardware flow control.
Do NOT use a null modem with a computer that has a standard COM port configured
as a DTE.
The DLS 6700 stops transmitting data when the RTS line is low, and restarts when the
RTS line is high. The DLS 6700 lowers the CTS and the DSR lines when it cannot
accept data, and raises them when it can. Note that the RTS line is not the usual
“Request To Send” as defined by the RS-232 standard. You can leave the RTS line set,
and use only the CTS line.
Most serial port communication programs can be used to control the DLS 6700. Any
ASCII terminal emulator can be used. Configure it to add linefeeds and echo typed
characters locally.
4.1.1 Message Terminators
Messages sent to the DLS 6700 through the serial interface MUST be terminated with
the line feed character (ASCII <LF>, decimal 10, hex 0A). To ensure that no charac-
ters are left in the receive buffer of the DLS 6700 from a previous incomplete com-
mand, you can send the line feed character by itself before sending new commands.
Messages from the DLS 6700 are always terminated with a Line Feed character.
Note that some languages, such as BASIC, may automatically append a carriage
return and a line feed at the end of messages. The carriage return character is not a
valid terminator, and will invalidate the last command. To avoid this problem, you can
append a semi-colon after a string (after the quotes) when printing to the communi-
cation port. Another solution is to append a semi-colon at the end of the command

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Page 4-2 7104000557 Spirent Communications
itself (inside the quotes), so that the carriage return can be interpreted as a second
command, and be simply discarded by the DLS 6700. For example:
PRINT #1, “:set:channel:line 1”+CHR$(10); Preferred solution
OR
PRINT #1, “:set:channel:line 1;” Alternate solution
4.1.2 Example using the RS–232 Interface
To change the length of the line to 4000 ft, do the following:
1) transmit “:SET:CHAN:LINE 1, 4000 ft”
2) check that the REMOTE LED is still green; if it turns red, see Section Chapter 5
"TROUBLESHOOTING".
To send and receive messages with error checking follow these steps:
1) set all relevant enable bits (only done once)
2) send the message
3) read the answer until you receive LF (decimal 10, hex 0A)
4) check if an error occurred with the command *ESR?
For example, to get the identification message with the RS–232 interface, do the fol-
lowing:
1) transmit “*ESE 60” enable all the error bits (needed only once)
2) transmit “*IDN?” query the identification message
3) read the answer the messages are always terminated with LF
4) transmit “*ESR?” check if an error occurred
5) read the answer. If not 0, an error has occurred. See Event Status
Register (ESR) Section for description of the error(s)
4.2 Data Formats
The DLS 6700 adheres to the IEEE 488.2 principle of Forgiving Listening and Precise
Talking.
The data formats supported by the DLS 6700 are:
Talking: a) <NR1> Numeric Response Data – Integer
b) Arbitrary ASCII Response Data
<NR1> is an implicit point representation of an integer.
Arbitrary ASCII Response Data is a generic character string without any delimiting
characters. It is usually used to send data in response to a query, such as with the
*IDN? command (see Section Section 4.5 "Common Command Set").
Listening: <NRf> Decimal Numeric Program Data
<NRf> is the Flexible Numeric Representation defined in the IEEE 488.2 standard
which can represent just about any number.
The DLS 6700 can accept data in the <NRf> format, which means that numbers can
be made of a combination of digits, signs, decimal point, exponent, multiplier, unit
and spaces. For example, any of the following is a valid representation for 4000 feet:
4kft, 4.0kft, 4000, .04e2k, 0.4 e4 ft, +4000. If a unit (i.e. ft, m, bps, etc.) is
appended to a number, that unit must be valid and not abbreviated. Note that the
period separates the decimal part of a number.

Chapter 4: REMOTE CONTROL
Spirent Communications 7104000557 Page 4-3
4.3 Command Syntax
The DLS 6700 adheres to the IEEE 488.2 format for command syntax. As with the
Data Format, the principle is Forgiving Listening and Precise Talking.
Commands may take one of two forms: either a Device Dependent Command starting
with a colon (Section Section 4.3 "Command Syntax") or a Common Command start-
ing with a star (Section Section 4.5 "Common Command Set"). Each type may be pre-
ceded by one or more spaces, and each must have one or more spaces between its
mnemonic and the data associated with it.
Common commands are preceded by the character “*”. Device Dependent commands
are preceded by a colon, with a colon separating each level of the command. Com-
mands may be either in upper or lower case. Multiple commands may be concate-
nated by separating each command by semi-colons.
The following are some examples:
*RST
*RST;*WAI;:SET:CHANNEL:LINE 1, 4000 ft
*ESE 45; *SRE 16
Messages to the DLS 6700 must be terminated with a Line Feed character (ASCII
<LF>, decimal 10, hex 0A). Messages from the 6700 are always terminated with a
Line Feed character.
As defined in the SCPI specifications, a Device Dependent Command may be sent in
its short form or long form, in upper or lower case. The following commands are
therefore identical in operation:
:SET:CHANNEL:LINE 1, 4000 ft
:SET:CHAN:LINE 1, 4000 ft
Queries of the system follow the same format as the commands, except that the data
normally associated with a command is replaced by a question mark “?”. Following
receipt of such a command, the DLS 6700 will place the appropriate response in the
output queue, where the controller can read it. Examples are:
*IDN?
*ESE?;*SRE?
:SET:CHAN:LINE?
When a command does not begin with a colon, the DLS 6700 assumes that the com-
mand is at the same level as the previous command. For example, to set a line one
does NOT need to specify “:SYS:CAL” each time, as in:
:SYS:CAL:Date Dec 2001;Expiry Dec 2002
This shorter form is valid because both LINEs are at the same level.
4.4 Device Dependent Commands
As recommended by the SCPI consortium and to simplify programming of the various
Access Emulation Division simulators, the DLS 6700 uses the following tree structure:
:SETting
:CHANnel

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Page 4-4 7104000557 Spirent Communications
:LINE <Line Number>,<Length>
:SYStem
:CALibration
:DATe <date>
:EXPiry <date>
:SYStem
:COMMunicate
:SERial <date>
:ECHo <Off|ON>
Each section of the command may be sent in the full or the truncated form (indicated
in upper case). The command itself may be sent in upper or lower case form.
The DLS 6700 will round any number to the nearest number permitted by the resolu-
tion of the parameter.
Sections Section 4.2 "Data Formats" and Section 4.3 "Command Syntax" give more
information on the data format and the command syntax.
4.4.1 :SETting:CHANnel:LINE <Line Number>,<Length>
Select the reach (length) of the line, where <Line Number> is the line number is a
valid line according to the model of the unit (1 to 8, 1 to 12, or 1 to 18), and
<Length> is the length of the simulated line.
The length of the DLS 6726 can be adjusted to between 1 kft and 24,000 kft in 1,000
ft increments.
For example, to set the length of line 1 to 4,000 ft, send:
:SET:CHAN:LINE 1,4000 ft
To set the length of all the lines to 4,000 ft, send:
:SET:CHAN:LINE 1,4000 ft
The units of the length are optional, but they must be in “ft” if present for the
DLS 6726. For more details on the numeric format supported by the DLS 6700, see
Section 4.2 "Data Formats".
To query the length of line currently simulated by the DLS 6700 send:
:SET:CHAN:LINE 1?
The command will return the line number, the current length followed by the unit's
minimum length, the maximum length, length incremental step size, and the gauge
(26AWG). For example, if the length of line 1 is 4 kft, and can vary from 1 to 24 kft in
1,000 ft steps, and is a 26 AWG gauge, the returned message will be:
1,4000 FT,0,24000,1000,26AWG
If there is no simulated line at the <Line Number>, then the DLS 6700 will return
“<Line NUMBER>,NONE”. For example:
17,NONE
4.4.2 :SYStem:Communicate:serial:echo <Off|On>
Set the echo off or on. For example:
:sys:comm:ser:echo on

Chapter 4: REMOTE CONTROL
Spirent Communications 7104000557 Page 4-5
When the echo is on, the DLS 6700 will echo back all the characters sent to the unit
and display the prompt character “>”.
To query the echo state, send:
:sys:comm:ser:echo?
Note: New units leaving the Access Emulation Division facility will have the echo set
to off.
4.4.3 :SYStem:COMMunicate:SERial:PACE <pace>
Set the receiver and transmitter pace method (flow control) of the serial interface,
where <pace> is any of the following choices:
NONE | CTS | RTS/CTS | XON/XOFF | ALL
For example, to set the pace method to RTS/CTS, send:
:SYS:COMM:SER:PACE RTS/CTS
NOTE
The new pacing must be used immediately for any further serial
communication.
To query the current pacing method send:
:SYS:COMM:SER:PACE?
The command will return the pacing method as a string. For example, if the pacing
method is RTS/CTS, the returned message will be:
RTS/CTS
To simplify the setting of the serial interface, we used a slightly modified SCPI com-
mand set. The SCPI standard requires separate settings for the RTS/CTS flow control
and XOn/XOff pacing, and differentiates between the receive and the transmit sides.
The command set of the DLS 6700 combines the “:RTS” and the “XON” settings into
one “:PACE” command.
Note that the SCPI standard assumes a DTE configuration, whereas the DLS 6700 is
configured as a DCE port (thus not requiring a Null Modem).
4.5 Common Command Set
As specified in the IEEE 488.2 standard, a number of common commands are
required to set up and control the standard functions of remote-controlled devices.
These common commands are as follows:
*CLS Clear Status Command
Type: Status command
Function: Clears the Event Status Register (ESR). Clearing the Event Status Reg-

DLS 6700 Operating Manual
Page 4-6 7104000557 Spirent Communications
ister will also clear ESB, the bit 5 of the Status Byte Register (STB). It
has no effect on the output queue (bit 4 of the STB).
*ESE <NRf> Event Status Enable
Type: Status command
Function: Sets the Event Status Enable Register (ESER) using an integer value
from 0 to 255, representing a sum of the bits in the following bit map:
Bits 7 to 0 have values of 128, 64, 32, 16, 8, 4, 2 and 1, respectively.
For example, if bits 3 and 5 are set then the integer value is 40 (8+32).
On power-on, the register is cleared if the Power-on Status Clear bit is
1, or restored if the bit is 0 (see *PSC for more details).
*ESE? Event Status Enable Query
Type: Status command
Function: An integer value between 0 and 255 representing the value of the
Event Status Enable Register (ESER) is placed in the output queue.
The possible values are described in the *ESE command section, and in
more detail in Section Section 4.6 "Status Reporting".
*ESR? Event Status Register Query
Type: Status command
Function: An integer value between 0 and 255 representing the value of the
Event Status Register (ESR) is placed in the output queue. Once the
value is placed in the output queue, the register is cleared. The com-
mand will turn the REMOTE LED green if the LED was red. The possible
values are described in the *ESE command section, and in more detail
in Section Section 4.6 "Status Reporting".
*IDN? Identification Query
Type: System command
Function: Returns the ID of the unit. Upon receiving this command the DLS 6700
will put the following string into the output queue:
SPIRENT COMM. INC,DLS 6700,<SN>,<Ver>
where: <SN> is the serial number of the unit