udev rule (file /etc/udev/rules.d/modem.rules):

SUBSYSTEM=="tty", ATTRS{idVendor}=="12d1", ATTRS{idProduct}=="1001", SYMLINK+="modem_huawei_$env{ID_USB_INTERFACE_NUM}"

Ensuite, il faut prendre en compte le changement

sudo udevadm control --reload-rules
sudo udevadm trigger

sudo apt install gammu gammu-smsd python3-gammu

sudo usermod -aG dialout gammu
sudo usermod -aG dip gammu
sudo chown -R gammu.gammu /var/spool/gammu

dip est le groupe pour démarrer pppd par l'entremise de wvdial

[gammu]
# Please configure this!
port = /dev/modem_huawei_02
connection = at19200
# Debugging
#logformat = textall
 
[smsd]
service = files
logfile = syslog
pin = 115200
# Increase for debugging information
debuglevel = 0
 
# Paths where messages are stored
inboxpath = /var/spool/gammu/inbox/
outboxpath = /var/spool/gammu/outbox/
sentsmspath = /var/spool/gammu/sent/
errorsmspath = /var/spool/gammu/error/

Préparation de la conf

sudo systemctl stop gammu-smsd
sudo systemctl disable gammu-smsd
rm /etc/init.d/gammu-smsd

Default config /etc/default/gammu-smsd

DAEMON_OPTS=""
 
# user to use (gammu is default)
GAMMU_USER=gammu
GAMMU_GROUP=gammu

Configuration du fichier systemd de gammu-smsd /etc/systemd/system/multi-user.target.wants/gammu-smsd.service

[Unit]
Description=SMS daemon for Gammu
Documentation=man:gammu-smsd(1)
After=mysql.service postgresql.service network-online.target
 
[Service]
EnvironmentFile=-/etc/default/gammu-smsd
# Run daemon as root user
#ExecStart=/usr/bin/gammu-smsd --pid=/var/run/gammu-smsd.pid --daemon
# Run daemon as non-root user (set user/group in /etc/sysconfig/gammu-smsd)
ExecStart=/usr/bin/gammu-smsd --user=${GAMMU_USER} --group=${GAMMU_GROUP} --pid=/var/run/gammu-smsd.pid --daemon
ExecReload=/bin/kill -HUP $MAINPID
ExecStopPost=/bin/rm -f /var/run/gammu-smsd.pid
Type=forking
PIDFile=/var/run/gammu-smsd.pid
 
[Install]
WantedBy=multi-user.target

Then the restart of the gammu-smsd daemon

sudo systemctl daemon-reload
sudo systemctl start gammu-smsd