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The Train Buddy's FAQ's on DCC:

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1. Is the Lenz LH90 compatible with the Digitrax Zephyr as a secondary throttle?

2. I am going to look into some kind of block detection to show occupancy on my control panel.  Does the Digitrax system work with a LENZ system?  Does Lenz make something similar?

Lenz vs. Digitrax

Q. Is the Lenz LH90 compatible with the Digitrax Zephyr as a secondary throttle? 

A. Short answer: no.
 
Long answer: The Lenz LH90 throttle uses a 5 pin DIN (round) plug, similar to that used on the older PC keyboard.
Lenz calls their communications protocol Xpressnet.  The basic difference is that Xpressnet is a protocol that was designed around Xbus, a hardware and software network bus designed for interconnecting instrumentation. The hardware design is based on RS-485 specification which originally had a network design limitation of 32 loads. This design limitation is really because of the number of bits used in addressing.  Otherwise it has no real hardware limitation as you may add networks by several means.  Going beyond the 32 total loads however, would make it incompatible with other RS-485 networks.  It is polarity sensitive, i.e. pin 1 to pin 1, 2 to 2, etc.  You must generally make and test your own cables.  The RS-485 specification states that you should terminate long runs and high speeds.  It is not normally necessary for Xpressnet.  It has a lot of support in the electronics arena.  Any limitations for length, termination, cable pinouts or number of devices then are up to the installer.  Xpressnet is a polled, deterministic network similar to Token Ring.
On the flip side Digitrax's Loconet is an Ethernet style (opportunistic) system with a non-polled interface.  This means that Digitrax devices can be plugged together without cable polarity concerns.  It works with off-the-shelf (rolled or straight through) 6 wire telephone wiring both front and back, no adapters needed for 5 pin DIN. You would usually adhere to the same straight through guidelines for Xpressnet and most make their own cables.  The devices can intra-communicate (an SE8C can talk to a BDL162) without a master console or polling computer.  There is a limit to the number of controllers, throttles, devices that are to be plugged into it but they are not limited by the protocol.  All of this is touted by Digitrax as more user-friendly.  It comes at a slightly higher cost for this flexibility.  Loconet can also get bogged down with messages and message delivery under extreme network loading.
The choice is really up to the end user but the bottom line remains the same, they are NOT interchangeable. 
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Q. I am going to look into some kind of block detection to show occupancy on my control panel.  Does the Digitrax system work with a LENZ system?  Does Lenz make something similar?

 
A. Unfortunately, the Digitrax system for signaling does not work with Lenz.  This is because the interface to the power booster is Loconet instead of XpressNet. (see above answer to first question) Simply, this is similar to the problem in the networking industry between Ethernet and IBM's Token Ring.  Lenz's system is the polled deterministic (Token Ring) network and Digitrax is the non-polled opportunistic (Ethernet) network.
You can use the Digitrax BLD162 with SE8C without using the LocoNet connections.  This will work fine if you just want to do signaling by block detection or put a few lights on your panels. It can detect up to 16 blocks, control up to 32 3-light signal heads and up to 8 Tortoise or other motors for semaphores.  It has the capability of having a fourth aspect for each head.  This can be flashing red, yellow or green and may also be dark for approach lighting.  It will not do anything for you (assuming you stay with Lenz for your throttles and command system and Digitrax for your signalling) if you want to eventually go to a PC driven layout.
I'm afraid the Lenz approach is more complicated with three modules being required, LB-101 and LR-101.  LR-101 will handle up to four LB-101's with each LB-101 handling two blocks.  This is a total of 8 blocks being detected per LR-101.  You would then need an LS-110 to run the signals and they (without additional circuitry) only handle two (red/green) lights per section and an LS-110 has 4 sections.  The LS-110 is comparable to a Digitrax DS-54 which does basically the same thing and is also limited to two lights.  Both the LS-110 and the DS-54 were originally designed for turnout control, not for signal control, hence Digitrax's entry of the SE8C.  Lenz does not have a competing product yet, however, I am told that one is on the way.
Another alternative is to build your own.  (Or buy them from Train Buddy)  I have built numerous current, light and no-light detection boards that I use on my layout for signaling and panel lighting.  They don't interface with Loconet (yet) but...they do the detection and provide panel lights, three light signals and crossover protection at three places on the Train Buddy layout.
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Kim Parker
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Revised: November 18, 2006 .

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This page was last updated: 2008-07-26