Package statserial

A tool which displays the status of serial port modem lines

ftp://metalab.unc.edu/pub/Linux/system/serial/

The statserial utility displays a table of the signals on a standard
9-pin or 25-pin serial port and indicates the status of the
handshaking lines. Statserial is useful for debugging serial port
and/or modem problems.

General Commands
Command Description
statserial display serial port modem status lines