sab, sabtty —
Infineon 82532 Enhanced Serial Communication Controller
  (ESCC2)
sab* at ebus?
sabtty* at sab? channel ?
The sab driver provides TTY support for the Infineon
  (previously Siemens) 82532 serial communications interface found in many Sun
  Ultra workstations and servers.
Input and output speeds for each line may be set to any baud rate
    in the following list: 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800,
    2400, 4800, 9600, 19200, 38400, 57600, 76800, 115200, 153600, 230400,
    307200, 460800, 614400, 921600.
The speed cannot be changed on the ports connected the Remote System Control
  (RSC) on a Sun Enterprise[tm] 250 Server (ttyh2 and ttyh3). These ports are
  fixed at 115200 baud.
  - /dev/ttyh[0123]
- serial ports
  - sab*: ring overflow
- The software input “ring” has overflowed. This usually means
      input flow-control is not configured correctly (i.e. incorrect cable
      wiring).
Thesabtty driver first appeared in
  OpenBSD 3.1 and was then ported to
  NetBSD 2.0.