The SPROG family of DCC devices

Use the table to select the best SPROG to meet your needs.

For use mostly as a programmer we recommend the SPROG II or Pi-SPROG 3 v2.

For layout control we recommend the SPROG 3, Pi-SPROG 3 Plus or SPROG 3 plus.

	SPROG II	SPROG 3	Pi-SPROG 3 v2	Pi-SPROG 3 Plus	SPROG 3 Plus (Future Product)	SBOOST II
Service Mode Programmer	Yes - in programmer mode	Yes - in programmer mode	Yes - in programmer mode	Yes	Yes	No
Ops Mode Programmer	Yes - in command station mode	Yes - in command station mode	Yes - in command station mode	Yes	Yes	No
Command Station	Yes - in command station mode	Yes - in command station mode	Yes - in command station mode	Yes	Yes	No
Booster	Integrated	Integrated	Integrated	Dual integrated	Dual integrated	Yes
DCC Outputs	1	1	1	2	2	1
Current Limit	1 Amp	2.5 Amp	2.5 Amp	2 x 2.5 Amp	2 x 2.5 Amp	2.5 Amp
Hardware Interface	USB	USB	R-Pi GPIO (UART)	R-Pi GPIO (UART)	USB	DCC
Software Interface	Proprietary	Proprietary	CBUS via GridConnect	CBUS via GridConnect	CBUS via GridConnect	N/A
Software Support	Windows, Linux, MacOS	Windows, Linux, MacOS	Raspberry Pi OS (Linux)	Raspberry Pi OS (Linux)	Windows, Linux, MacOS	N/A
Layout Accessory Control	DCC	DCC	DCC	DCC, CBUS®	DCC, CBUS®	N/A
Layout Feedback	None	None	None	CBUS	CBUS	N/A
Auto-reverse	No	No	No	Yes on 2nd output	Yes on 2nd output	Yes

Service Mode programmer

A service mode programmer can read and write Configuration Variables (CVs) on a dedicated programming track. With the Pi-SPROG 3 Plus and SPROG 3 Plus the programming track may be connected directly to the layout, allowing locos to be driven onto the programming track without being removed from the layout.

Ops Mode programmer

An ops mode (also known as on-the-main) programmer can write CVs anywhere on the layout. Readback of CVs is not possible in ops mode with SPROG DCC products.

Command Station

The command station creates the DCC signal that is sent across the rails to locos and accessories on the layout.

Booster

A booster allows the output of a command station to drive a layout by increasing the maximum current that may be consumed. SPROG DCC products (apart from SBOOST II) all include an integrated booster (two in the case of the "Plus" products. The SBOOST II is a stand-alone booster that may be used to further increase the current avaiable to the layout.

DCC Outputs

Each DCC output must be connected to an isolated section of the layout (e.g. inner loop and outer loop or "up" and "down" lines. These sections of the layout are known as "power districts". Furthe power districts may be created using SBOOST II or other boosters. Trains may cross between power districts with no ill-effect.

Current Limit

The maximum current that the booster can supply to the layout before it shuts down.

Hardware Interface

SPROG DCC products connect to a host computer via USB or a Raspberry Pi GPIO connector or, in the case of SBOOST II, to the DCC signal from a command station or other booster.

Software Interface

Early SPROGs use a very simple proprietary interface to pass commands from the host computer to the SPROG. Newer products (SPROG DCC Generation 5) use a much more complex protocol known as CBUS to allow for greater flexibility and functionality.

Software Support

The recommended software for SPROG DCC products is JMRI® which is free open-source software. Other software packages (e.g. TrainConbtroller, RocRail) have been known to support SPROG DCC products but you should check with the respective vendors for the current status

Layout Accessory Control

Accessory control allows control of items such as turnouts and signals. All SPROG DCC products support DCC accessory control when used with suitable software such as JMRI. The "Plus" products also support layout control via CBUS.

CBUS

CBUS is a layout control bus originally developed by MERG members. CBUS is based on CAN bus technology and allows the connection of multiple Model Railway devices such as throttles (cabs), command stations, accessory control and feedback. For a more detailed description (under construction - will appear soon) click here.

Layout Feedback

Feedback of layout information (e.g. block occupancy detection) is supported only by "Plus" products, via CBUS. Other SPROG DCC products can be combined with other manufacturers' feedback busses (e.g. XpressNet, LocoNet®)

Auto-reverse

Auto-reverse is the ability of a booster to reverse the polarity of the DCC signal when an overload is detected. The simplest example of this is for wiring a reverse-loop. SPROG DCC "Plus" products support auto-reverse on one output. SBOOST II also supports auto-reverse when configured to do so.

CBUS® is a registered trade mark of Dr Michael Bolton.
JMRI® is a registered trademark of the JMRI Community
LocoNet® is a registered trademark of Digitrax, Inc.