[P25nx] Connect to astrotac

[Bryan Fields]

On 12/19/20 8:13 AM, Larry D'Anna wrote:
> Are there software settings in cisco and Atac i can look at to determine if the clocks are set correctly?
> Should the Atac be configured for internal vs external clock as I have it now?

No, what I was saying is that Motorola does clocking of sync serial different
than the standard.

Fist some definitions:
DCE - Data Communications Equipment (network gear) - provider of clock
DTE - Data Terminal Equipment (non-network gear) - slave to DCE clock
Master Clock - A clock source
Slave Clock - a device that will not send data without a Maser Clock

So the Cisco must be DCE and a Maser Clock.  The quantar/atac/diu is a DCE and
will not send data until it has clock from the DCE.  In standard sync serial
DTE gear when configured for slave clocking is the DTE uses it's receiver
clock sent by the DCE to clock it's transmitter.  The DCE doesn't provide
clock on it's receiver (DTE transmitter) clock line, only the DCE Transmitter
clock (DCE receiver clock).  This means the clock for the DTE must come from
the DTE, but locked to DCE clock being sent.

Quantars/ATAC/DIU's don't do this.  When configure for Slave Clock the ATAC
will not clock it's transmitter from the receiver.  To get the transmitter to
clock, you must connect the RX clock and TX clock lines.

The only way to check this is with an oscilloscope on the clock lines.  The
ATAC and Quantar provide basically no debugging of the serial interface, which
is no uncommon for early 90's gear.  Most people working with serial
interfaces would have a debug or test set to verify this.

So if you have a connector miswired or something not configured correctly,
debugging it is all kinds of fun.  What you need to ensure is the ATAC is set
to slave clocking and the cisco set to master.  This should work, provided the
connections to the router are wired properly.

What errors do you get while it's running?  Are you testing on a locally
connected quantar to the atac?

-- 
Bryan Fields

727-409-1194 - Voice
http://bryanfields.net