UmTRX aka OpenBTS HW update

Alexander Chemeris alexander.chemeris at
Tue Oct 11 13:16:05 UTC 2011

Hi Jean-Samuel,

On Tue, Oct 11, 2011 at 17:11, Jean-Samuel Najnudel - BJT PARTNERS
SARL <jsn at> wrote:
> Hi Alexander,
> I looked at the schematics and PCB. I did not notice anything bad. However,
> I am not really able to check everything.
> Anyway, I just have two questions.
> 1/ There is a CLKIO connector. As I can see on the schematics. We can set
> this as a clock output (master) or input (slave). This looks perfect if we
> want to synchronize 2 boards together (1 master output connected to 1 slave
> input). If we need to synchronize 3 boards together (trisector
> configuration), how could we connect them together ? Can we split the clock
> output signal to connect it to the 2 slave inputs ? If yes, everything is
> fine. If not, we might need 1 ouput and 1 input on the board (instead of 1
> output or 1 input) to allow us to daisy chain the boards. What do you think?

Andrey says we can connect 3 to 5 units to a single output easily. We
just need to make a "splitter-cable".

> 2/ On Image2, I can see 3 components outside the board near the 6 pin
> connector. Is this normal ?

Yes this is normal, as layout is not 100% finished yet. If there is no
serious objections or additions, we're going to start final layout
iteration immediately. It will take about a week more to polish

Alexander Chemeris.

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