Tracing the apparently-unused MODEM UART signals

TxD from Calypso: ball B9, L1 trace goes to (3905,1100).  Found it on L2, goes
to an inner via at (3914,1070).  Found the inner via on L7, goes to (3182,1071).
On L8 the signal goes directly to the debug connector identified by steve-m.

RxD to Calypso: ball A9, seems to have a micro-via under the ball, pad coords
(3888,1054).  Found it on L2, goes to an inner via at (3911,1030) and also to
what looks like a via back to L1 at (3858,1228).  The stub back to L1 appears
to be a pull-up resistor.  Found the inner via on L7, goes to (3154,928).
On L8 the signal goes directly to the debug connector identified by steve-m.