Scan modem
From Gentoo Wiki
scanModem a software tool that finds a suitable driver for a connected modem. scanModem is not available in gentoo.git, so it has to be manually downloaded and extracted:
user $
wget https://web.archive.org/web/20190722162705/http://linmodems.technion.ac.il/packages/scanModem.gz
user $
gunzip scanModem.gz
user $
chmod +x scanModem
user $
./scanModem
It will create a folder Modem and the file scanout.something contains the wanted information. If a modem is detected, the driver is named next to Drivers, e.g. for a HSF modem:
Driver=hsfmodem-drivers