It's a program you use to connect to devices over serial ports (including via modem), and it has file-transfer capabilities built-in. I first started using it w

It's a program you use to connect to devices over serial ports (including via modem), and it has file-transfer capabilities built-in. I first started using it with my HP-48SX calculator in the 90s. It's still the first tool I reach out when communicating over serial devices, e.g. SBCs that don't have a graphical console like running OpenBSD over a BeagleBone using the UART to connect, or Cisco switches using the serial cable.