iphone as a gsm modem

Google is giving me conflicting answers... I want to dial a remote gsm device via my iPhone plugged in to a PC but I'm not seeing anything that looks like it might be a modem when I do lsusb. This is obviously different than just having a data connection to the internet as the remove device isn't connected to the internet - I need to dial it directly. Can the iPhone be used as a GSM modem or is that deemed too 'legacy' these days? I'm hoping there is a usb switch app I can run to enable the modem USB interface but I'm not optimistic. Thanks James