DCC Pocket Tester
Attention DCC geeks, here is the ideal
Test DCC Signals to Verify Your Power Boosters
and Track are working the way they should! Fast, Powerful,
Accurate, and Track Powered!
The DCC Pocket Tester is the only low-cost,
portable, reliable, and accurate way to test and verify the DCC
Protocol. The unit is completely powered from the DCC Signal, so
no batteries to change, no power cord to remember, and NO PC
required, which makes it the ultimate tool for your toolbox.
- Bit Summary -
A good quick-view into your DCC system from the Bit Level.
- Bit Totals -
Detail showing the Total Bits, as well as the Total ONE and
Total ZERO bits.
- Bit Timing
- Bit Errors
- Packet Summary
- Packet Timing
- Packet Lengths
- Packet Errors
- Address Summary
- Address List
- Data Summary
- Data Monitor
The DCC Pocket is a product of
Pricom Design. There are two versions available:
Complete DCC Pocket Tester (Black)
Includes the DCC Pocket Tester, 24" Alligator Clip Test Lead
Set, PC Serial Cable for Firmware Updates, and printed users
Lite Edition DCC Pocket Tester (Black)
Includes the DCC Pocket Tester (Lite Edition), 24" Alligator
Clip Test Lead Set, PC Serial Cable for Firmware Updates, and
on-line users manual. Does not support One Bit Timing, Zero Bit
Timing and Bit Errors.
Pricom Design has released a DCC pocket tester.
It measures 5 .75 x 3.63 x 1.25, so it will just fit into your
pocket. It is designed to read the quality of the DCC data on
your layout. Through the use of 17 different menus, the measured
data are presented in various formats that allow you to
completely examine how your DCC system is performing on your
Pricom website states that the unit is designed for people
“building a DCC Command Station, Power Booster, or other DCC
Powered Device”, so the DCC Pocket Tester is not designed as
tool for use by all model railroaders. Small layouts will not
benefit from the use of the DCC Pocket Tester unless you simply
like to add gadgets to your layout. Large club layouts, however,
might want to consider adding a DCC Pocket Tester to their
arsenal of DCC equipment. Large layouts can start to show
problems in DCC due to the length of the track runs. As the
length of the track becomes longer, the layout can start to act
as a transmission line. This means that the layout is large
enough that the DCC pulses take a significant amount of time (in
electrical time at least) to move around the layout. Earlier
pulses can reflect from various points in the layout. Due to the
time it takes them to move from one point to the other, they can
actually interfere with later DCC pulses. In essence, this
effect can cause DCC errors and strange, random behavior. Also,
on large layouts, the amount of DCC traffic on the rails can
cause response delays due to packet congestion. The DCC Pocket
Tester is the tool of choice to help analyze these types of
The DCC Pocket Tester has a 2.6 x 1.5 LCD dot
matrix display. This allows the internal processor to show the
measured data in a multi-line user friendly format. The unit has
four “arrow” buttons for navigating through the various menus. A
simple power connector ties the unit to the track. This input
provides the DCC data and the power to operate the unit; no
batteries or other power source are required. In addition to the
power input, there is an RS-232 port for downloading software
upgrades, and a PNET port for attachment to the Pricom RS-485
network. A SEL button is not mentioned in the directions, but
appears to reset the measurements in each menu.
The unit I received had Version 1.0 software.
The website indicated that the latest configuration is Version
1.3. I downloaded the PC Update software, the new configuration
file, and a .NET file from the Pricom website. Per the user
manual, I first installed the .NET software. This is actually
software from Microsoft that relates to the installation
environment. I then installed the Pricom Universal Uploader
software. I followed the user manual directions and connected
the DCC Pocket Tester to my computer's COM 1 RS232 port using
the included cable and then started the upgrade software. I
followed the user manual directions for updating the unit, and
found that everything worked smoothly as stated in the
instructions. Although the .NET file is over 23 MB and took some
time to download, I had no problem at all upgrading the unit to
Version 1.3. Pricom is to be commended for their smooth, simple
approach to upgrading software.
After upgrading, I connected the DCC Pocket
Tester to my layout. The initial Quick Summary menu showed the
DCC system working correctly. The next menu, Bit Summary, showed
normal bit operation. This menu also contains an indication of
the DCC voltage. With a DCC voltage of 13.9 volts, the Pocket
Tester read 13.7 to 14.0. This is somewhat more error than their
stated value of 1%. The directions do say that this reading is
not RMS, and therefore is approximate. I found that the fast
update rate for the voltage made it difficult to read the tenths
of a volt digit since it was continually changing.
Several menus give statistics on the length of
one and zero bits and the number of bits failing to meet NMRA
standards. These menus can help large layouts if there is bit
interference problem. A packet summary menu gives the total
packet count and the number of bad packets. This menu also gives
the packet rate. On large layouts, control response can be
limited by the packet rate. This is essentially how many
commands can be sent in a second. With a large number of
operating engines, the packet rate can limit the response time
of an engine or accessory to a cab command.
Rather than detailing all of the menus here, I
recommend that you go to the Pricom website (see above) for a
detailed description of all of the DCC Pocket Tester functions.
One problem I did find: the Pocket Tester does not have a
separate display function for accessory addresses. Engine
addresses and accessory addresses use different formats. The DCC
Pocket Tester interpreted accessory addresses as engine
addresses. The result is that some of the menus were
contaminated with incorrect addresses that resulted from issuing
macro commands to accessories. For example, the Pocket Tester
reported the use of address 9465. This address is actually an
accessory address interpreted as if it were an engine address.
Hopefully, a future update will correct this problem and provide
a separate menu item for accessory addresses.
The DCC Pocket Tester is a well designed unit
intended mainly to help verify command station and booster
performance. For large layouts with high traffic volumes, the
DCC Pocket Tester is useful to help determine where and when DCC
errors are occurring. It can help isolated bit distortion and
packet congestion problems that manifest themselves as unstable
performance on large layouts. The DCC Pocket Tester is easy to
upgrade, with Pricom indicating on their website the intention
to provide future performance improvements as they are
Used with permission of AHD.
Copyright © 2004-2005 by AHD. All Rights Reserved.