NCE Power Pro Serial Port Issues.


Occasionally a modeller has an issue getting a computer program like JMRI’s Decoder Pro to communicate with the Power Pro.


Ensure the Power Pro Command Station Settings for Baud Rate are set for 9600 and the AIU Broadcast, is DISABLED.


This issue can be caused by an intermittent connection in the Serial Port circuitry that sometimes can be fixed by removing the two Hexagonal Headed Screws that secure the Serial Port to the FRONT Panel, shown left with the applicable screws removed. NOTE: I am NOT talking about the Screws in the USB to Serial Adaptor Cable.


See the bottom of the page for the Loopback Test that checks the USB to Serial Adaptor and Cable for continuity and operation.













These Screws are too long/high and can restrict the USB to Serial Adaptor’s Plug, from engaging with the Power Pro’s Serial Port Socket.  













Removal of these Hexagonal Headed Screws can fix the connection, BUT…..


Some early Command Station have LOOSE Nuts to secure these Screws and the Nuts may spin or if you can remove the screws, the Nuts may float around inside the Power Pro unit – not good for electronics.


Later Command Stations, the Nut is a part of the Assembly securing the Serial Port to the Circuit Board. See the photo left that also shows the USB to Serial Adaptor Plug installed.


With the Top off you can see if you have loose Nuts or not and take the appropriate action.


Then plug in your USB to Serial Adaptor Cable and test for operation of Decoder Pro etc.














For a more permanent installation, using your Dremel with a Cut Off Disc, trim about a 1.5 mm of the Head of the Hexagonal Head Screws as shown left. The Securing Screws of the Adaptor Cable Plug will NOT screw in all the

way but you’ll have a “connection”.












With the Hexagonal Headed Screws removed and a successful Loopback Test below, if Decoder Pro does still not work, you may have a faulty Upper Command Station Circuit Board. The Power Pro box needs to return to NCE for check/repairs.



Loopback Test.



TURN OFF Decoder Pro.

Remove the USB to Serial Adaptor Cable from the Power Pro.

Using a Clip etc. I used a small Jumper Lead.

Short out Pins 2 & 3 of the Cable Serial Plug (not the Serial Port on the Power Pro), as shown in the photo.

Be careful not to touch the metal shell of the Plug.



Start Up Decoder Pro.

On the Opening Window (Roster).

Select Help.

Select System Console







A successful Loopback Test, the words “timeout flushes receive buffer: AA” will appear in the System Console text as shown below.

This confirms JMRI received a reply to the AA command it sent, verifying continuity of the wiring and operation of the USB to Serial Adaptor.


2018-01-01 21:27:16,807 jmrix.AbstractMRTrafficController  WARN  - Timeout on reply to message: AA consecutive timeouts = 0 in nce.NceTrafficController [nce.NceTrafficController Transmit thread]

2018-01-01 21:27:16,909 nce.NceConnectionStatus                 WARN  - Incorrect or no response from NCE command station [nce.NceTrafficController Transmit thread]

2018-01-01 21:27:16,911 jmrix.AbstractMRTrafficController  WARN  - timeout flushes receive buffer: AA [nce.NceTrafficController Receive thread]


If you cannot see the words “timeout flushes receive buffer: AA”:


Recheck the shorting out of Pins 2 & 3 “connection”.

Exit Decoder Pro.

Open up Decoder Pro.

Open up the System Console

The screen should be clear then shows lines of text.

Hopefully in the bottom 3 lines of text, “timeout flushes receive buffer: AA” will show in the bottom line.


If not, you have a faulty USB to Serial Adaptor or Cable.