Modem emulator used by the oFono mobile telephony stack

 oFono is a stack for mobile telephony devices on Linux. oFono supports
 speaking to telephony devices through specific drivers, or with generic
 AT commands.
 .
 Phonesim is a modem emulator that oFono uses for development and testing.
 This allows oFono to be used by any host without requiring special GSM
 (or other) hardware.