Can anyone tell me what is required in order to use the MTH- DCS System. And, what is the difference between DCC and DCS. I can't find for example decoders for the engines, is the wiring different than DCC. Can you just hook up the system to your tracks and run trains?
Just curious.
Robert Sylvester, WTRR
DCS is a proprietary system that is only for MTH products, and is not NMRA DCC compliant.
More recent MTH locomotives are becoming DCC compliant, but there are still many NMRA DCC configuration variables that are not supported.
You can run the newer DCS engines on DCC systems. Other than MTH engines, DCC-equiped locomotives will not run on DCS. DCS engines are not fully compliant with the DCC standards.
You can't buy DCS decoders separately. They are only available in MTH engines. While MTH engines are relatively nice and more of them are being produced in HO all the time, the selection is still rather limited. They would be considered "high-end" products to most buyers.
In short, if you run your railroad with DCS, you are limited to the engines produced by MTH. If you run your railroad with DCC, you can run any DCC engine by any manufacturer as well as almost all of the engines built by MTH for the HO scale market.
It takes an iron man to play with a toy iron horse.
If you're running HO, save yourself the trouble and stick with DCC.
The best way I could describe it is that I once bought a Betamax player. I didn't know that VHS had become the standard. When I would go to the video store the selections I had was a single rack with 2 sides. The rest of the store was VHS. It really sucked to see everyone else having all of the variety and selection and I was stuck with the limited DCS, oops Betamax.
Springfield PA
The Betamax comparison is a good one, and not just for the reasons stated. Sony held on to all the rights to Betamax, while Phillips (if I recall correctly) licensed VHS to anyone. MTH has kept its DCS system proprietary, so only MTH can sell them. DCC, on the other hand, was first developed by Lenz, but they basically gave the rights to the NMRA, and made the specifications publicly available to anyone who wanted to develop their own DCC equipment. The result has been a reasonable number of DCC manufacturers, and even better, any DCC engine will run on any DCC system.
Let's hear it for innovation.
Hi Robert,
robert sylvester Can anyone tell me what is required in order to use the MTH- DCS System.
Can anyone tell me what is required in order to use the MTH- DCS System.
To run DCS you need locomotives equipped with either Protosound 2 or Protosound 3 decoders and one of three DCS command hardware options. The least expensive option is the DCS Remote Commander (#50-1033) which is sold separately for $40, but is included in most MTH starter sets. The DCS RC is a small IR remote that has limited access to sound features and can only run one locomotive address. The mid level option is the DCS Commander (#50-1028), which sells for $150. The Commander has access to far more sound and control features than the DCS RC and can run multiple locomotive addresses, but cannot consist locomotives. The Commander also has a built in DC throttle that can be used to run conventional locomotives. Both the DCS RC and the Commander were introduced in recent years as stripped down versions of DCS aimed at people getting into command control for the first time. The original, and still the only full featured version of DCS, is the DCS set with a TIU (track interface Unit) and cab (#50-1001), which sells for $300. The DCS set gives access to all sound, control, and programming features in PS2 and PS3 locomotives. It can also control AIU's (accessory Interface Units) which are sold separately for $100. Each AIU has 10 SPDT (ON)-OFF-(ON) momentary relays and 10 SPDT ON-ON latching relays for the control of turnouts and accessories.
what is the difference between DCC and DCS.
DCS and DCC use two very different technologies to achieve very similar goals. To give a better picture of the differences it's better to break this into two categories: the command system and the decoders.
Both command systems send digital instructions to locomotives. The technology used to send the digital instructions (1's and 0's) is different. DCC takes DC electrical current and swaps the polarity back and forth rapidly. The time between polarity swaps defines a 1 (52-64 microseconds) or a 0 (90-10000 microseconds). The main advantage of this technology is that command communications are quite reliable and diagnostics are easily understood by most hobbyists. Basically, if you have good electrical continuity you will have good command communications. There are sacrifices for using this technology. The bandwidth for digital communications is relatively low. The communications are inherently one-way, so locomotive decoders can't talk back to the command hardware. Digitrax and Lenz have tried to address the lack of two-way communications with their transponding and RailCom systems. However, Digitrax transponding relies on proprietary decoders and Loconet hardware, and RailCom decreases the available bandwidth even more. The switching transistors used to swap track polarity are cheap and readily available for low amperage systems. However, high amperage high speed switching transistors are a boutique item in the electronics industry. This is one of the reasons DCC boosters of 5 amps and larger are so expensive. The fact that DCC is an open standard also has pluses and minuses. Others have already mentioned the main plus, interoperability. The minuses are cost and slower development of new technologies. No one DCC manufacturer has been able to capture enough of the market to achieve large economies of scale, such as spreading out R&D costs. While competition between DCC manufacturers has been strong, no one manufacturer can push the technology very far or very fast because substantial changes must be approved by the MNRA DCC Committee before they will gain wide spread acceptance. Lenz's RailCom system took nearly eight years to gain acceptance from the DCC Committee with RP-9.3.1.
DCS on the other hand keeps the command signal separate from the power current, which can be either AC or DC. Other systems in the 70's and 80's also attempted to send command signals over the rail separate from the track current and failed. DCS succeeded by taking advantage of spread spectrum technology and encoding methods that were too expensive for the hobby market until the late 90's. Even with this new technology large layouts (500 sq. ft. and larger) often have signal issues with DCS. Smaller layouts are usually plug and play with little or no tweaking required for reliable communications. This technology addresses most of the shortcomings of the DCC polarity swapping signal technology. DCS has about 100 times the digital bandwidth of DCC and natively supports two-way communications. The bandwidth is sufficient to support streaming audio. You can use a microphone built into the cab as a radio to communicate between crews, or make your own station announcements. The audio is directed to the active locomotive on the cab. All commands sent by DCS to a locomotive prompts a reply from the locomotive back to the cab. This lets the system know when a command has been received so it doesn't need to be repeated, cutting down on unnecessary digital traffic. Separating the digital signal from the track current has significant cost savings. To duplicate the capacities of a DCS set and one AIU (MSRP $400) with NCE hardware costs over $1800. The fact that DCS is a proprietary system has pluses and minuses, just as DCC being open. The pluses are that MTH has a sizable market in scales other than HO for DCS. Since they control 100% of the DCS market they are able to spread costs across a business that appears to be larger than any one DCC manufacturer. Competition with DCC and Lionel's Legacy command control system has prevented them from having a true monopoly, which has kept DCS prices constant. They also have great flexibility to develop new technology without waiting for committee approval. The down side, of course, is that you have only the options MTH provides. In O-scale there's not much you can't do with DCS because MTH has produced hundreds of different models and offers decoder kits. In HO the options are currently more limited.
The decoders available for each system and their capabilities are the other part of the DCC/DCS comparison.
DCC decoders are available in a plethora of sizes, amperage capacity, capabilities, and prices. DCS decoders are an all or nothing proposition. They only come as sound decoders with outputs for lights, smoke, couplers, etc. The biggest technological difference between a PS2 or PS3 decoder and high end DCC decoders is how they handle speed control. Currently, all DCC decoders with speed control use BEMF to infer motor speed. In contrast PS2 and PS3 decoders use an optical sensor to measure actual motor speed. The optical system is two orders of magnitude more accurate than the available BEMF systems. There's no reason another DCC manufacturer couldn't use this more accurate technology, but right now none of them do. MTH's Protosound 3 decoders function on either DCS or DCC. Regardless of which control system is being used they have the same high precision speed control.
MTH take advantage of this tighter speed control in several ways. First, they have established a consistent speed map. Because MTH manufactures both the locomotive models and the decoders they are able to account for wheel diameter, gear ratio, and flywheel size and program each model to run at the same speed. Unlike most BEMF DCC models, PS2 and PS3 locomotives can operate with mid-train and/or rear helpers in a single consist without causing derailments even on varying grades. Second, MTH has implemented two forms of record/playback capability. Subway, trolley, and interurban models come with a programmable station stop feature. Each unit can be programmed to run a point to point or continuous loop route. The model runs for a recorded amount of time at a set speed between stops. Since speed and time are repeatable, so is the distance. Station stops are rarely off by more than 1 inch. The more elaborate version of record/playback works with the entire layout including turnouts and accessories. Any command that the DCS system can issue can be recorded and played back. We used this system on a layout I helped complete in time for the NMRA's National Convention is Seattle in 2004. The layout hosted two bus tours. With the record/playback feature we were able to operate six trains sharing a single track main on a point to point model of the Alaska Railroad. We never could have operated more than one or two trains with so many people crowded into the layout room. Instead we were able to put on a good show and still pay attention to the visitors.
There are a few other ways that MTH has taken advantage of the two-way communications between decoders and the DCS command hardware that are not duplicated in DCC. Protosound 2 and 3 locomotives have the ability to upload their ID#, name, cab number, available functions, and other data directly to the DCS cab. You can also query any locomotive for its distance traveled, hours of usage, current track voltage, and other data on the mainline.
The biggest features found in DCC that DCS doesn't have are an open PC interface for layout automation and 4-digit engine ID's. DCS only supports 2-digit ID's.
I can't find for example decoders for the engines
MTH offers separate sale PS2 decoders in O-scale and G-gauge.
They have said publicly that they will offer PS3 decoders in HO, but have not yet done so. The decoder kits that they have sold in O and G have always included speakers, lights, and all necessary wire harnesses and mounting brackets. I think it is safe to assume that when they do release PS3 decoders in HO they too will be packaged with all the necessary hardware. There are no entry level decoders for DCS.
is the wiring different than DCC.
It's a little different. Both systems allow you to get rid of block wiring and all the toggle switches that go with it. With DCC the preferred wiring method is to run two bus wires around the layout with feeder wires to the track every so often. With DCS, especially on larger layouts, it's better for command signal quality to run a pair of wires from each feeder location back to the TIU. It's counter intuitive, but both methods usual require about the same amount of wire. This is largely because DCS works better with fewer feeders compared to DCC.
Can you just hook up the system to your tracks and run trains?
Yes. If you have PS2 or PS3 locomotives you plug in the command hardware and go. It's no more or less complicated than DCC. In fact, the user interface and easy engine loading process with two-way communications makes the initial learning curve easier than most DCC systems.
Hope that helps.
You description is excellent, and I agree to your description of the tradeoffs. But there is one I believe rather large shortcoming of DCS, largely as a result of being proprietary. It is very difficult to put a DCS system under computer control. With very complex layouts, like I have with my MTH layout, this is a frustrating step up I seem to not be able to make. Do you agree, and if not, do you have any suggestions as to how to accomplish this. thanks, paul
Dave, thats the best explanation I have read about DCS. I have a couple more questions, how is polarity in reverse loops and dog bones handled and what are the channels on the TIU used for?
Thanks Rick