Serial Format; Handshake Procedure - W&T Rs232 Multi Computer Adapter Handbuch

W&T
RS232 Multi Computer Adapter

Serial format

Baud rate, number of data bits and any parity bit which may be
used can be configured separately for each port on the
T-switch, so that the format can be adapted to any connected
terminal device.

Handshake procedure

All serial ports on the T-switch can be set to hardware
handshake or XON/XOFF handshake independently of each
other. Operating the T-switch with no handshake is not
recommended.
When one of the internal buffers in the T-switch is nearly filled
with data, an XOFF code (13H) is output on the corresponding
port and for the next received character the hardware hands-
hake output is set to ‚Block' (negative level). Once the buffer
has been emptied again, an XON code (11H) is output and the
hardware handshake output is set to ‚Enable' (positive level).
If the T-switch receives an XOFF code or detects a block level
(negative level) on the hardware handshake input, it stops
sending data on the corresponding port no later than one byte
after this state is detected. If the T-switch receives an XON code
or detects an enable level (positive level) on the hardware
handshake input, it resumes sending data.
The XON and XOFF codes are used only for the handshake;
these codes are not data and are also not allowed to be
contained in the user data. If a hardware handshake is used
however and the T-switch is correspondingly configured, the
XON and XOFF codes are treated as normal data.
Subject to error and alteration 11