TIU Differences

All REV. L TIUs have a USB port.  The plastic housing used on the REV. L is different from every previous version.

Here's a quick run through TIU history... (BORROWED FROM DAVE HIKEL - HERE)

Rev. G - This was the original, released in April, 2002.  Unlike all later TIU's, the Rev G's had the black terminals on all four channels tied together.  They are also the only TIU revision without internal blade fuses and were vulnerable to shorting out with older transformers with slow acting breakers.  The G's can be identified on the outside by the lack of a revision sticker on the underside.  The G's also have a "ProtoSound 2" logo painted on the top of the case.

Rev. H1/H1A/H1B/H2/H2A - The "H" revisions added the blade fuses for auxiliary circuit protection and isolated the black terminals on each channel.  The G and H revisions all used 5 volts chip sets.  The various alpha numeric iterations within the "H" revisions represented minor hardware changes on the circuit board.  All "H" revisions came with an identifying sticker centered on the underside of the case.  The H1's were painted with the "ProtoSound 2" logo, but from the H1A on MTH switches to the DCS oval logo on the top of the case.

Rev. I/I1/I1A/I3/I3A/I3B - The "I" revisions moved from a 5 volt to a 3 volt chip set.  The various alpha numeric iterations within the "I" revisions represented minor hardware changes on the circuit board.  All "I" revisions came with an identifying sticker centered on the underside of the case.  MTH used a sans serif font on the revision stickers, which has often lead to confusion.  Many people mistake the "I" for a "1."

Rev. L - So far there has only been a single variation of the Rev. L.  The L uses a 3volt FPGA chip set with improved signal recognition, which effectively improves track signal quality.  The "L" also added a USB-B port, which can be used in lieu of the RS-232 port to connect the TIU to a PC for updating firmware and transferring files.  You can identify the Rev. L by the sticker and the USB-B port.

@H1000 posted:

Here's a quick run through TIU history... (BORROWED FROM DAVE HIKEL - https://ogrforum.com/...40#36484918588547540)

H1000,

Just a little heads up.  The link doesn't work.

Mike

Maybe I have a weird version of the TIU.  My TIU says Rev. L on the bottom of the case but it has the serial port.  There is not a USB port anywhere.  This unit was bought new  in 2018 from a MTH retailer.  Thanks for the onfo on the different revisions.  Not overly concerned about input port.  Ordered a USB to Serial cable so I can update the software,

@otww posted:

Maybe I have a weird version of the TIU.  My TIU says Rev. L on the bottom of the case but it has the serial port.  There is not a USB port anywhere.  This unit was bought new  in 2018 from a MTH retailer.  Thanks for the onfo on the different revisions.  Not overly concerned about input port.  Ordered a USB to Serial cable so I can update the software,

I'd guess it's not a REV. L, it would be very easy for a NOS H or I revision to be sold by a dealer. I ordered a new TIU from Trainworld back in 2015 and they sent a REV. I. I sent it back and specifically requested a REV L.

If you can upload some pictures of the bottom and sides it would be interesting to see. To accommodate the USB port, the MIC input port had to be moved and the housing had to be changed with it.

@otww posted:

Maybe I have a weird version of the TIU.  My TIU says Rev. L on the bottom of the case but it has the serial port.  There is not a USB port anywhere.  This unit was bought new  in 2018 from a MTH retailer.  Thanks for the onfo on the different revisions.  Not overly concerned about input port.  Ordered a USB to Serial cable so I can update the software,

Would you mind posting a couple pics of the ends?  I’d love to see it.

The Rev. L has both a serial port and a USB port.

This is a picture of the USB port on a Rev. L TIU.  It is a USB port type "B".  That's not always pointed out on these threads so some folks might miss it.

It's not the familiar Type A USB port like this one:

The USB Type B port is the port for peripherals, look at any USB disk drive, printer, etc.  It certainly should be recognizable!  Since the TIU is connected to a computer using this port, the USB Type B port is what you should expect to see!

My bad.  When I looked at my type L I saw the serial port on the end marked pC input. Did not pay attention to the other end where the unmarked USB Type B port is located.  Since I ordered a USB type A to nine pin Serial cable I will just have to use that to update the TIU.  Makes me wonder why the wizards who designed this thing didn't mark or label the USB type B port.  Every other input on the device is labeled as to purpose.

So in the rev L world, they got two modifications that I know of after the first release.  There was the TVS small diode mod to protect the Transmit chips.  Would be a silver dot applied after the mod.  Then the second generation was larger TVS diode.  The applied silver dot is sporadic depending on who modified it, and no specific add on I have seen for TIU with later larger diode install.  The G, H and I had a whole bunch of rolling modifications that really predate when I entered this, and it was not well documented in the MTH training documentation provided to techs.  So you can see all kinds of minor mod to fix an issue that must have occured.  G

@gunrunnerjohn posted:

The USB Type B port is the port for peripherals, look at any USB disk drive, printer, etc.  It certainly should be recognizable!  Since the TIU is connected to a computer using this port, the USB Type B port is what you should expect to see!

Thanks for the computer lesson but I don't just shove a cable into a device and the other end into something else without knowing the purpose.  The USB B shhould have been labeled as pc input just like the serial port was or at least it should have been installed next to the serial port and  it would have been obvious that both were for pc input.

Well, I can't argue that they should have labeled the port, that seems an obvious omission.

@gunrunnerjohn posted:

Well, I can't argue that they should have labeled the port, that seems an obvious omission.

I even checked the owners manual and there is no reference to the USB in the diagram which id's the tiu ports.  Looks like the port as installed was an after thought and placed whereever they could find a spot on the case and be supported internally.  I've had problems with that unit which required that it be sent back to Columbia for repair and I'm very hesitant to attach anything to the unit unless I know exactly whats what.  Thanks for the info.

The User's Manual was never updated for the Rev. L TIU.