Usage

Once the set-up is complete you may start communicating with the modem. Ensure you have already connected the transducer then start the modem by executing the startmodem.sh script. The full path to run the main file from the user directory will be

/home/modem/moda/dev-toolbox/scripts4trials/startmodem.sh

This command will run the test-modem process with the default settings. Most parameters can be conveniently changed by editing the startmodem.sh file. The table below lists them.

Modulation-independent parameters

Parameter	startmodem.sh label	Possible values
ID (source address)	id	int [1;15]
Carrier frequency	carrier	int (Hz)
Modulation technique	modulation	flex,janus,flexofdm
Output amplifier gain	gain	float [0.01;0.99]

Flexframe-specific parameters

(only evaluated when modulation=flex or modulation=ofdmflex)

Parameter	startmodem.sh label	Possible values
Modulation	flex_psk	Listed in Overview
Interpolation	interpflex	int [5;20]
Inner FEC scheme	intFEC	Listed in Overview
Outer FEC scheme	outFEC	Listed in Overview

JANUS-specific parameters

(only evaluated when modulation=janus)

Parameter	startmodem.sh label	Possible values
Bandwidth	bandwidth	int (Hz)

Communication

Once the startmodem.sh script is up and running, the modem opens a TCP socket on port 55555 to communicate with the user. You may use netcat to connect to the socket, typing

nc <SuM IP address> 55555

Alternatively, the socket can be opened locally: open another SSH terminal and connect to the modem (as in quickstart) then type

nc localhost 55555

Afterwards data can be sent and received through the terminal.

Having problems transmitting/receiving data? Take a look at the troubleshooting section.

Toggling autostart

If you wish the modem to start listening and transmitting to the socket port 55555 automatically after startup you may enable the autostart service by typing

sudo systemctl enable sumd.service

In order to disable the autostart feature instead type

sudo systemctl disable sumd.service