Dnp3 Tutorial

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DPS Telecom
“Your Partners in Network Alarm Monitoring”
DNP3 Tutorial:
Learn the Industry-Standard SCADA Protocol
Version 1.0
Released August 21, 2012
www.dpstelecom.com • 1-800-622-3314
“We protect your network like your business depends on it”
TM
This guide will teach you...
-The fundamentals of DNP3
-How to understand DNP3 communication
-8 Important Considerations in DNP3 SCADA Systems
Read this guide to learn how to get started with DNP3
today...
DNP3 packet structure
2
© Copyright 2012 DPS Telecom
All rights reserved, including the right to reproduce this white paper or portions thereof in any form without written
permission from DPS Telecom. For information, please write to DPS Telecom 4955 E. Yale Ave., Fresno, CA 93727-1523
1-800-622-3314 • [email protected]
Printed in the U.S.A
DNP3 • DPS Telecom • 4955 East Yale Avenue, Fresno, CA 93727 • (800) 622-3314 • Fax (559) 454-1688 • www.dpstelecom.com
How This White Paper Will Help You
This DNP3 reference guide was written for you, the professional who needs to monitor SCADA equipment with
DNP3. Most DNP3 books go way too deep and just aren’t practical. Who has time for all that?
I’ve written this DNP3 tutorial to give you the information you need to successfully implement and maintain
DNP3 monitoring in your SCADA system. It’s an introduction to SCADA from your own perspective, and it
has the fast, specific answers you need to make DNP3 work for you...
Contents
Part 1: An Introduction to DNP3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
DNP3 Uses a Master/Remote Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Part 2: How DNP3 Elements Communicate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Part 3: Understanding the DNP3 Object Library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Part 4: Understanding the DNP3 Message Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Part 5: Understanding Layered Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
A Critical Tool for Troubleshooting Communication Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Traversing the Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Part 6: 8 Important Considerations in DNP3 SCADA Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
DPS Telecom Guarantees Your Success - or Your Money Back . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
What to Do Next . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
About the Author . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3
DNP3 • DPS Telecom • 4955 East Yale Avenue, Fresno, CA 93727 • (800) 622-3314 • Fax (559) 454-1688 • www.dpstelecom.com
4
DNP3 • DPS Telecom • 4955 East Yale Avenue, Fresno, CA 93727 • (800) 622-3314 • Fax (559) 454-1688 • www.dpstelecom.com
DNP3 uses a Master/Remote Model
DNP3 is typically used between centrally located
masters and distributed remotes. The master pro-
vides the interface between the human network
manager and the monitoring system. The remote
provides the interface between the master and the
physical device(s) being monitored and/or con-
trolled. The master and remote both use a library
of common objects to exchange information. The
DNP3 protocol contains carefully designed capa-
bilities that enable it to be used reliably even over
media that may be subject to noisy interference.
Part 1: An Introduction to DNP3
Since its introduction in 1993 as an immediately
deployable solution for monitoring critical infra-
structure status and allowing reliable remote con-
trol, Distributed Network Protocol (DNP or DNP3)
has achieved widespread acceptance. GE-Harris
Canada (formerly Westronic, Inc.) is generally cred-
ited with the seminal work on the protocol but it is
now implemented by an extensive range of manu-
facturers in a variety of industrial applications.
DNP3 is based on an object model that greatly
reduces the bit mapping of data that is traditionally
required by other less object oriented protocols. It
also reduces the wide disparity of status monitoring
and control paradigms generally found in proto-
cols that provide virtually no pre-defined objects.
Purists of these alternate protocols would insist that
any required object can be ‘built’ from existing
objects. Having some pre-defined objects though,
makes DNP3 a somewhat more comfortable design
and deployment framework for SCADA engineers
and technicians.
DNP3 Gear
T/Mon LNX
T/Mon SLIM SCADA Guardian
When seeking out DNP3 equipment, it is im-
portant to find a unit that will give you the most
functionality for your money. DNP3 gear typical-
ly pays for itself several times over by preventing
lost revenues from outages by maximizing your
network uptime. Deploy a DNP3 RTU today,
and get superior visibility and control over your
network.
A typical DNP3 master/remote
monitoring system architecture.
Visit www.dpstele.com/rtus or call 1-800-693-0351 for
more SNP3/SCADA equipment
5
DNP3 • DPS Telecom • 4955 East Yale Avenue, Fresno, CA 93727 • (800) 622-3314 • Fax (559) 454-1688 • www.dpstelecom.com
Part 2: How DNP3 Elements Communicate
DNP3 uses 27 basic function codes to exchange information
between Masters (think Control Center) and Remotes (think
pump yard). Some of those function codes enable a Master
to request and receive status information from a Remote.
Other function codes enable a Master to determine or adjust
the configuration of a Remote.
Several function codes are defined for a DNP3 Master to
control the Remote itself or equipment co-located with
the Remote. One function code is provided to enable the
Remote to respond autonomously with an Unsolicited
Message to particular events that occur in its installation
space.
As you can see, most of the messages are issued by the
DNP3 manager to the DNP3 remote. However, because
the Unsolicited Message is capable of being initiated by a
Remote, it is typically used to report alarms. This notifies
the DNP3 Master as soon as an alarm condition occurs,
instead of waiting for the next request.
Part 3: Understanding the DNP3 Object Library
The DNP3 framework includes a library of objects that are
typically used in SCADA systems. This library is available
for downloading to members of the DNP Users Group; visit
www.dnp.org for more information. These objects include
such things as Binary Inputs that are used to report equip-
ment characteristics that have two states; power is on or off,
an access panel is open or closed. Another common object
is an Analog Input that is used to report characteristics that
have a range of values; exhaust fan speed can be anywhere
from 40 to 400 RPM, main power can vary from 110 to 128
VAC.
This library makes it easy for the manufacturer to design
the DNP3 Remote responder to use these common objects
to report to upstream Masters. It also makes it easier for
Masters to integrate the data collected from Remotes and
present it for decision making.
Without this framework of common objects, manufactur-
ers must develop their own model for reporting status and
providing control capability. These models, frequently quite
different one from another, must then be ‘compiled’ into the
Masters and usually converted into some kind of common
objects for efficient management. Another tool often found
in these more ‘open’ frameworks is a proprietary interface
Questions to Ask: Your
SCADA Site Survey
RTU Capacity and Function
1. How many sites do you need to moni-
tor?
2. Do you want video surveillance at those
sites?
3. Do you want a building access control
system to manage entry to those sites?
4. How many alarm points do you need to
monitor at each site?
5. How much growth, in sites and alarms at
each site, do you anticipate over the next
5 years?
6. Do you need any analog sensors (e.g.,
voltage, temperature, humidity, signal
strength)?
Installation
1. How do you currently connect to your
remote sites? (LAN, overhead, digital
or analog circuit, terminal server, micro-
wave?)
2. Do any of your sites support an alternate
path communications link?
3. What type of power do you have at the
master and remote sites? (–48 VDC, 110
VAC, other?)
4. How do you want to mount your RTUs?
(23” rack, 19” rack, wall, tabletop?)
5. Who will install your RTUs?
This is just a small sample of the DPS Telecom
SCADA Site Survey. The full SCADA Site
Survey is a complete 5-page guide to evalu-
ating your network alarm monitoring needs.
For your copy of the Remote Site Survey,
call DPS Telecom at 1-800-622-3314.
DNP3 • DPS Telecom • 4955 East Yale Avenue, Fresno, CA 93727 • (800) 622-3314 • Fax (559) 454-1688 • www.dpstelecom.com
6
or translation module to access and control the Remote.
Objects in the DNP3 library are divided into Groups and
Variations. For example, the Analog Input group has six
variations to provide 16 or 32 bit integer or floating point
values with or without a status bitmap. The Analog Event
group has eight variations to provide 16 or 32 bit integer or
floating point values with a status bitmap and with or with-
out a timestamp. Note that the Analog Event group does
not include variations without a status bitmap.
Part 4: Understanding DNP3 Message
Structure
Let’s examine the structure of the messages exchanged
between masters and remotes. Basic serial telemetry pro-
tocols, like TBOS, are byte-oriented, with a single byte
exchanged to communicate. Expanded serial telemetry
protocols, like TABS, are packet oriented with packets
of bytes exchanged to communicate. The packets contain
header, data and checksum bytes. DNP3 is also packet ori-
ented and uses the packet structure (element sizes in bits)
shown in the illustrated figure below.
The Master sends a Read request for an object or objects
and the Remote’s response contains the requested infor-
mation if available. The Master sends an Operate com-
mand to produce the output actions associated with the
selected object reference. The Remote sends an Unsolicited
Message when a specific event occurs.
The following figure shows the message packet format.
The DNP3 application service data unit (ASDU) is worthy
of special note for the clever content adjustment that is
controlled by the qualifier and indexSize fields. This design
makes application data available in an impressively flexible
number of configurations or omitted all together if desired.
Perfect-Fit Solutions DPS -
Without the NRE Fees
When choosing your DNP3 SCADA equip-
ment, shouldn’t you only pay for the things
you need? Many monitoring and SCADA
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isn’t like everyone elses’.
That’s why perfect-fit and fully customizable
engineering such a valuable tool. Instead
of overspending on equipment to get all of
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What can perfect-fit engineering do for
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ones you don’t.
• You’ll know that a device is going to fit
right into your network.
• Get guaranteed results with a 30 day
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http://www.dpstele.com/rtus
DNP3 packet structure illustrated.
Link
Transport
Application
D
N
P
3
L
a
y
e
r
s
7
DNP3 • DPS Telecom • 4955 East Yale Avenue, Fresno, CA 93727 • (800) 622-3314 • Fax (559) 454-1688 • www.dpstelecom.com
3 Advanced RTUs
The NetGuardian RTU family scales to fit
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NetGuardian 832A G5:
• 32 discretes, 32 pings, 8 analogs and 8
controls
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• 8 terminal server serial ports
• Dial-up backup
• Web browser interface
• Pager and email notification
• Dual -48 VDC, -24 VDC or 110 AC
• 1 RU for 19” or 23” rack
DNP3 RTU NetMediator 864A
• 64 discretes, 8 controls
• Reports alarms via DNP3 or SNMP over
LAN
• 1 RU for 19” or 23” rack
Economical NetGuardian 216
• 16 discretes, 2 analogs, 2 controls
• 1 terminal server serial port
• Single or dual -48VDC or 110 VAC
• 2 compact form factors for rack or wall
mount
http://www.dpstele.com/rtus
Part 5: Understanding Layered Communication
A Critical Tool for Troubleshooting Communication
Problems
We continue to examine the Distributed Network Protocol
(DNP3) focusing specifically on the layered communica-
tion model used to exchange information. The last section
focused on the structure of DNP3 messages and illustrated
the first few layers of the message.
The application layer combines an application service data
unit (ASDU), a packaged object in itself, with an applica-
tion protocol control info (APCI) block to make an applica-
tion protocol data unit (APDU).
The transport layer breaks the APDU into segments with a
maximum size of 16 bytes and packages them with an 8-bit
transport control header and 16-bit segment CRC separa-
tors into a transportFrame.
The link layer adds a header the control and addressing
information to prepare the packet for delivery to a specific
destination.
These layers can be mapped to the four-layer model devel-
oped by the Department of Defense (you may recall the
DoD origins of the Internet) with the DoD Internet Layer
omitted.
If the serial transport is used, the packet assembly is com-
pleted and placed on the transport media for delivery.
If the packet will be sent over a LAN/WAN, the three
DNP3 layers are rolled up into the application layer. The
assembled packet is wrapped in the Transport Control
Protocol (TCP) by the transport layer, which in turn is
wrapped in the Internet Protocol (IP) by the (somewhat
obvious) internet layer. The User Datagram Protocol (UDP)
can also be used but presents some additional issues related
to reliable delivery in congested networks
The fourth layer is the Network Interface layer where the
assembled packet is actually interfaced to some kind of
transport media (for example, twisted pair copper, RG58
co-axial or fiber). While this multi-layer model may seem a
bit confusing, it effectively isolates the tasks of communi-
cation and ultimately assists in designing and implementing
a network.
DNP3 • DPS Telecom • 4955 East Yale Avenue, Fresno, CA 93727 • (800) 622-3314 • Fax (559) 454-1688 • www.dpstelecom.com
8
Traversing the Layers
To illustrate the function of this layered model, let’s look
at a single DNP3 Read request over a LAN. The DNP3
Master wants to know the current status of the Remote’s
power and prepares a Read request message for the appro-
priate object. After passing through all three DNP3 layers,
the message is passed to the TCP/UDP transport layer.
The transport layer adds a data block that identifies the
Master port from which the request is sent and the port on
which it expects the Remote DNP3 process to be listen-
ing for messages. The packet thus formed is then passed
to the IP layer. Here a data block containing the IP and
Media Access addresses of the Master and the Remote is
added before the entire assembled packet gets passed to the
Network Interface layer. The Network Interface layer veri-
fies media access and availability and places the packet on
the media for transmission.
After working its way across bridges and through rout-
ers (the modern equivalent of over the rivers and through
the woods) based on the IP information, the packet finally
arrives at the Remote. Here it passes through the same four
layers in exactly the opposite order as it did at the Master.
First, it is pulled off the media by the Network Interface
layer. After confirming that the packet is intact and valid,
the Network Interface layer simply passes it to the IP layer.
The IP layer verifies the Media Access and IP address and
passes it on to the TCP/UDP layer where the target port
is checked for connected applications. If an application
is listening at the target port, the packet is passed to the
Application layer. If the listening application is the Remote
DNP3 process, the Read request is passed through its three
layers to validate the request and identify what information
needs to be collected. The Remote response then follows
the identical path in reverse to reach the Master.
An DNP3 message passes through the protocol layers at
both the manager and the agent. Each layer addresses a
specific communication task.
SCADA Guardian
Superior monitoring and control with
this DNP3 RTU
A SCADA environment relies heavily on
accurate information on a wide range of
variables to ensure that each part of a con-
trolled process happens when it should and
to the right degree. The SCADA Guardian
reports alarms via DNP3 or SNMP - making
for an easy integration into your SCADA
network.
This new RTU is densely packed, capable
of monitoring 24 external analog sensors,
so you can monitor temperature, flow, pres-
sure, and any other number of variables to
keep your SCADA controlled environment
running smoothly. Of the analog inputs, 16
are based on DPS Telecom’s convenient
“D-Wire” technology, in which the sen-
sor’s power and monitoring data are both
carried through the same cable.
To take control of your SCADA environ-
ment.
• Call 1-800-693-0351
• Email [email protected]
• Use the DPS website to submit a fast
information request
Don’t leave your network vulnerable any
longer - call the network monitoring spe-
cialists today at 1-800-693-0351.
9
DNP3 • DPS Telecom • 4955 East Yale Avenue, Fresno, CA 93727 • (800) 622-3314 • Fax (559) 454-1688 • www.dpstelecom.com
Part 6: 8 Important Considerations in DNP3
SCADA Systems
Using DNP3 in a contemporary SCADA system is an easy
decision. DNP3 is a standard protocol that has wide accep-
tance in the industry and is flexible enough for almost any
application. DNP3 certainly has its place in an effective
monitoring solution, but this doesn’t mean that any off-the-
shelf DNP3 Master or Remote will be a best fit for you.
Before you commit to an SCADA monitoring solution for
either your operating center or your remote sites, you need
to consider a multitude of factors.
Before you buy … check for these 8 important features:
1. Masters should provide concise alarm information
Masters sometimes present data in such an attractive,
graphical interface that you can’t see the forest for the
trees. Make sure that you have access to a list view that
provides a good presentation of event and alarm detail for
more than a single site or region. Sometimes, summary
graphical presentation can make detail an inconvenient
click or two away when a decision needs to be made.
2. Masters should be able to identify cleared alarms
If you will be relying on Unsolicited Messages in your
system, make sure there is a clear event for each alarm.
Creating this association can involve expensive custom
development on your Master system.
3. Masters should maintain a history of standing alarms
Avoid the allure of maintaining only an event log of
newly reported Unsolicited Messages and a history log
of acknowledged Unsolicited Messages. If an Unsolicited
Message represents an alarm condition, there should be
continuing visibility to the alarm even if the Unsolicited
Message is acknowledged. Imagine what might happen to
your network if a system operator acknowledges an alarm
message, and then, for whatever reason, fails to correct the
alarm condition. Who would know the alarm is still stand-
ing?
4. Masters should sort and filter alarms
Masters should support organizing alarms by a wide variety
of characteristics. Location, equipment type and severity
Let DPS Help You
Survey Your SCADA and
Monitoring Needs
A Free Consultation at No Obligation
to You
Determining your
SCADA and alarm
monitoring needs
can be tough. If
you’ve got a busy
job with a lot of
responsibilities, you
don’t have a lot of
time to evaluate
gear and survey
your remote sites.
So why not get help
from experts you can trust? DPS will
help you survey your remote sites step-
by step, making sure you don’t miss
any opportunities to make your net-
work monitoring project successful —
and easier on your budget.
A DPS expert consultant can help you
figure out what DNP3, SCADA, and
monitoring products will most effec-
tively meet your needs without over-
loading your budget. Our goal is to give
you the tools you need to help keep
your network up and running. With
an emphasis on maximizing ROI, we
don’t pressure you to buy a particular
system.
There’s no hard-sell sales tactics. No
harassing sales calls. No pressure to
buy. We won’t discuss specific equip-
ment options until we’ve helped you
plan the right monitoring strategy for
your network.
[email protected] or 1-800-693-0351
Eric Storm
President
DPS Telecom
DNP3 • DPS Telecom • 4955 East Yale Avenue, Fresno, CA 93727 • (800) 622-3314 • Fax (559) 454-1688 • www.dpstelecom.com
10
are just a few possibilities that may make sense for orga-
nizing your alarms. The same alarm should be able to be
posted to multiple categories. The presentation of sorted
and filtered alarms should depend on the user logged on;
the team responsible for generator maintenance doesn’t
need to wade through lists looking for generator events and
alarms.

5. Masters should support flexible and powerful notifi-
cation
Make sure your master support the advanced features nec-
essary for premium status monitoring, such as notification
escalation, nuisance alarm silencing, automatic control
relay operation, and automatic notifications by e-mail, text
or pager.
6. Masters should not be limited to DNP3
If you’re like most companies, you have a variety of
equipment of different ages and technologies. Integrating
this diversity into a SCADA Master can sometimes involve
surprisingly expensive customization or additional mod-
ules.
It is always difficult and uncomfortable to justify sig-
nificant development costs after purchasing an already
expensive SCADA Master. Why take the time, trouble, and
expense to recreate capabilities that are already present in a
high-quality, multi-protocol Master that is DNP3-capable?
7. Remotes should support redundant power.
If your remote is powered from a single source, then your
critical monitoring is vulnerable to a single event. Losing
that single source of power effectively compromises the
continuous monitoring of your revenue generating equip-
ment. If your installation does not have dual power sourc-
es, make sure the equipment is compatible with an external
uninterruptable power supply. Also insure that the primary
power is one of the points monitored at each location.
8. Remotes should provide local SCADA.
If a network failure compromises the collection of data,
your remote equipment should provide for local visibility.
Turn the worst case of having to dispatch techs to critical
remote sites into a much better case by insuring that they
will be able to browse to your remote units and have local
SCADA until the network is restored.
Alarm Master Choice:
T/Mon LNX
T/Mon LNX has many features to make
your alarms more meaningful, including:
1. Multi-protocol support, which
allows you to integrate many types of
equipment under a single monitoring
umbrella.
2. Immediate notification of COS
alarms, including new alarms and
alarms that have cleared.
3. Standing alarm list is continuously
updated.
4. Text message windows displaying
specific instructions for the appropri-
ate action for an alarm.
5. Nuisance alarm filtering, allowing
your staff to focus its attention on seri-
ous threats.
6. Pager and email notifications sent
directly to maintenance personnel,
even if they’re away from the NOC.
7. Derived alarms and controls that
combine and correlate data from mul-
tiple alarm inputs and automatically
control remote site equipment to cor-
rect complex threats.
For more information, check out T/Mon
on the Web at
http://www.dpstele.com/products/em/
tmon_lnx/
11
DNP3 • DPS Telecom • 4955 East Yale Avenue, Fresno, CA 93727 • (800) 622-3314 • Fax (559) 454-1688 • www.dpstelecom.com
DPS Telecom Guarantees Your Success — or
Your Money Back
When you’re choosing a network monitoring vendor, don’t
take chances. Be skeptical. Ask the hard questions. Above
all, look for experience. Don’t take a sales rep’s word that
his company can do custom development. Ask how many
systems they’ve worked with, how many protocols they
can integrate with DNP3, and check for client testimonials.
DPS Telecom has created hundreds of successful monitor-
ing implementations for telecoms, utility telecoms, and
transportation companies. (Check out http://www.dpstele-
com.com/dpsnews/success_stories for some examples.)
DPS Telecom monitoring solutions are proven performers
under real-world conditions. You’re never taking any risk
when you work with DPS Telecom. Your SCADA moni-
toring solution is backed by a 30-day, no-risk, money-back
guarantee. Test your DPS monitoring solution at your site
for 30 days. If you’re dissatisfied for any reason, just send
it back for a full refund.
What to Do Next
Before you make a decision about your SCADA DNP3
monitoring, there’s a lot more you need to know. There are
dangers you want to avoid — and there are also opportuni-
ties to improve your remote site maintenance that you don’t
want to miss.
Get the information you need. Send an e-mail to support@
dpstelecom.com for “A Practical, Step-by-Step Guide” on
how to implement SCADA monitoring in your network.
You can also call us today at 1-800-622-3314 to schedule
your free Web demo of SCADA monitoring solutions, or
register on the Web at www.dpstelecom.com/tmon-web-
demo.
7x24 Tech Support
(No Credit Card Required)
First-class tech support assists you
whenever you need
Every single prod-
uct offered by DPS
includes comprehen-
sive technical sup-
port. If you’ve pur-
chased DPS products
to implement in your
existing network
and have questions,
contact DPS Tech
Support today at
559-454-1600 or at support@dpstele.
com.
At DPS Telecom, the representa-
tive who answers your call isn’t an
intern reading from a script. DPS
Tech Support representatives are
engineers who contribute to product
development. And, if your problem
requires additional expertise, the
DPS Engineering Department that
designed your product is right down
the hall.
Now matter how tough or techni-
cal your question is, you’ll always
have the support you need from DPS
Telecom - even outside of standard
business hours. At no extra cost to
you, DPS offers 24/7 emergency
technical support. Just because
you have a network emergency at
3 in the morning doesn’t mean you
shouldn’t get the assistance you
need.
Chris Hower
Tech Support
DPS Telecom
“We had no doubt that whatever DPS
told us that they could do, they’d do it,
and they have. They’re very reliable
and we knew that the product was go-
ing to be reliable.
-Bill Young,
Consolidated Communications
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12
“We protect your network like your business depends on it”
TM
US $36.95
Marshall DenHartog has over ten years’ experience working with remote mon-
itoring and SCADA equipment, including designing network monitoring devic-
es, creating SNMP systems for multiple platforms, and developing SCADA
solutions for several nationwide networks.
DenHartog’s experience with both the theoretical and practical sides of
SCADA and alarm monitoring have equipped him to write a straightforward
guide to the DNP3 protocol.
Marshall DenHartog is also the author of the widely downloaded SNMP
Tutorial.
The DPS Promise from Eric Storm, President
I don’t think you should have to take any risks to get the monitoring and control capabili-
ties you need. If you decide to work with me, I won’t let you fail.
If my solution doesn’t solve your problems 100%, I don’t want you to have it. I have
three goals: I want to sell my product, I want you to use my product, and I want you to be
completely satisfied with my product.
If my product doesn’t fulfill those goals, I will fix it, improve it, or give you your money
back. If my stuff doesn’t wow you, I don’t want your business.
So here’s my guarantee to you: if you buy a DPS Telecom solution, you can test at your
site, under real-world conditions, for 30 days. If you’re dissatisfied with it, for any reason,
just send it back and you’ll get a full refund, no questions asked.
So please — if you’re interested in any of our products, do yourself a favor and call us
today at 1-800-622-3314. Your network’s needs can’t wait. I promise you — we’ll deliver
a solution to your problems, at no risk to you.
Sincerely,
Eric Storm,
President
Eric Storm
President
DPS Telecom
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