Some things to look at in regards to latence are min/time and edelay.
These can be set/viewed using ditty-rp:
View port settings:
# ditty-rp -a ttyxyz
If -icanon is set, you might want to tinker with the min and time values:
min N With -icanon, set N characters minimum for a completed read
time N With -icanon, set read timeout of N tenths of a second
The edelay setting is configured on a per port basis. This parameter changes the value we send to the firmware for "ttime" and "rtime".
By default edelay has always been set to 100ms with the lowest value of 1.
For example, when issuing the following setting:
ditty-rp edelay 1 /dev/ttyzz01
It tells the firmware the ttime/rtime is 1ms.