Hardware Support: CTI Acela System
As described in the Acela documentation
on the CTI web site
several CTI modules are available:
- A CTI Acela module (currently only released with a
serial interface) that performs most of the low-level CTI
- A CTI SmartCAB module which when used on a non-DCC
model railroad, controls the trains in a traditional CAB
system. The CTI SmartCAB module is not supported by
- A CTI TrainBrain (4 output relays and 4 input
- A CTI Dash-8 (8 output relays, no input circuits).
- A CTI Watchman (8 input circuits, no output
- A CTI SignalMan (16 output circuits, no input
- A CTI SwitchMan (16 output circuits, no input
- A CTI YardMaster (16 output circuits, no input
- A CTI Sentry (no output circuits, 16 input
- A CTI network is usually connected to a computer via a
CTI to serial (or CTI to USB) interface. In this
configuration all of the CTI network management must be
performed by the computer. CTI also offers an Acela module
(currently only released with a serial interface) that
performs most of the low-level CTI network management. JMRI
only supports the CTI Acela interface (it does not support
the direct serial -- nor USB interface).
- A CTI network can be used on either a non-DCC or a DCC
model railroad. When used on a non-DCC model railroad, CTI
uses SmartCAB modules to control the trains in a
traditional CAB system. JMRI only supports the CTI system
when used on a DCC railroad and does not support SmartCAB
- CTI input sensor modules (Train-Brain, Watchman,
Sentry) support five different types of input sensors:
Infrared, Current Detection, Push-Button, Magnetic Reed
Switches, and Photocell. JMRI now supports all of these
- CTI input sensor modules support unique configuration
of each sensor (inverted, debounce, threshold). JMRI now
allows you to
If the hardware is connected, nodes (CTI modules) are
found automatically at startup. Nodes can also be defined
manually with the
Configure Nodes tool. Either way, don't forget to save
them with the "Save" button on the Preferences
window (under Edit in the main menu).
The CTI Acela network is a true token passing ring
network. Each module has two "four wire phone jacks". One
labelled with a RED circle and the other labelled with a
GREEN circle. To complete the ring, you should connect a
straight through four wire cable from the GREEN jack in one
module to the RED jack in the next module. The last cable
should connect the GREEN jack in the last module back to the
RED jack in the first module.
The CTI Acela module has the same RED and GREEN jacks as
well as a third YELLOW jack. The CTI Acela module should be
placed somewhere in the ring just as any other CTI
For the CTI Acela module a special four wire cable should
be connected from the YELLOW jack into the serial port of the
controlling computer (or a serial to USB converter).
Once powered on and started, if the red LEDs on each
module are not flashing then the ring is broken (either no
power to one or more modules or a bad cable or the cables are
daisy chained wrong or a cable has become loose).
For completeness, on power up, each CTI module has a solid
RED led lighted.
Once the Acela network is up, the red LED on each module
will flash as a packet passes by (so you basically see all of
the nodes flashing rapidly -- almost in sync).
The Acela module itself is different in that it always
flashes a green LED to indicate that it is happy (whether the
ring is happy or not).
JMRI Acela Tools
Naming of CTI Acela inputs and outputs is described on a
Third Party info
More information on the Acela hardware can be found on the