Novaterm 9.6 User's Guide
hardware. See section 1.1.3, Selecting a serial device for a
description of each driver.
4.6.2 Flow control
Flow control allows Novaterm to keep up with incoming data. When
Novaterm falls behind in processing incoming data, Novaterm tells
the remote computer to pause until Novaterm catches up. When
Novaterm is nearly caught up, it tells the remote computer to resume
transmission. This prevents characters from being lost. Flow control
is done automatically, but it may be turned off by toggling this option.
Novaterm supports two types of flow control:
Software (XOFF/XON): In software flow control, Novaterm sends
an XOFF character (usually CTRL-S) to pause and an XON character
(usually CTRL-Q) to resume.
Hardware (RTS/CTS): In hardware flow control, Novaterm tells
your modem to stop delivering data to the computer by lowering the
RTS line (one of the RS232 port pins). In this state, the modem stores
incoming data in a buffer until Novaterm to stop giving it data by
lowering the CTS line (which can happen in the remote computer has
lowered its RTS line). Hardware flow control is much more precise
and reliable than software, since modems respond immediately to
changes in RS232 lines. However, to use hardware flow control, you
must have at least a 9600 bps modem. Most slower modems (2400
bps and below) do not respond to the RTS and CTS lines, so hardware
flow control is not possible with them.
If you are using a high speed modem (9600, 14.4k or 28.8k) you
must use hardware flow control to take advantage of data compression
and error correction, and to enable Novaterm to keep up with
incoming data (see 4.1.2, Baud rate).
At speeds of 2400 bps and below, flow control is not necessary, and it
can be set to None.
4.6.3 Flow tolerance
The "flow tolerance" specifies the number of characters that may
build up in the receive buffer before Novaterm stops the flow (using
either hardware or software flow control). Since the receive buffer
holds a maximum of 256 characters, the tolerance may be any number
between 6 and 256. The default setting is 220, which is effective for