You will want to take a look at the input processing flags for the port(s):
# ditty-rp -a ttyxyz
ignbrk, brkint, ignpar, parmrk, inpck, istrip, inlcr, igncr, icrnl,
In most cases these should be off (-).
Also, parity (checking) may impact this, as well. You will want to look over your parity configuration on the port and attached device.