HP 16550A User Reference page 56

The Format Menu
Pod Clock Field (State only)
When the analyzer sees a match between the slave clock input and the Slave
Clock arrangement, Demux Slave data is latched. Then, followed by a match
of the master clock and the master clock arrangement, the slave data is
strobed into analyzer memory along with the master data. If multiple slave
clocks occur between master clocks, only the data latched by the last slave
clock prior to the master clock is strobed into analyzer memory.
Analyzer Memory
Pod 1
Latching Slave Data In Demultiplex Mode
4–18
Slave Latch
Pod 2 is not connected
Master
Clock
Slave
Clock