D-Modem on Windows¶

D-Modem's daemon, dmodemd, runs on Windows 7 and later as a single dmodemd.exe that needs nothing else installed. It is the same modem as on Linux: it makes calls over SIP (internet telephony), handles data, fax and voice, and can drive the USB modems D-Modem supports.

For build options, every way of connecting a program to it, and how the port works, see the technical details.

Status: the Windows version is built and tested automatically, both under Wine on Linux and on a Windows build server (GitHub's Windows Server 2022 machines). Nobody has yet run it by hand on a desktop Windows, or with a real USB modem.

Building¶

You can build it on Linux for Windows:

sudo apt-get install cmake ninja-build pkg-config g++-mingw-w64-x86-64-posix clang lld
cmake -B build-win -G Ninja -DCMAKE_TOOLCHAIN_FILE=platforms/windows/mingw-w64.cmake
cmake --build build-win

Or on Windows, from a Developer Command Prompt for Visual Studio 2022:

cmake -B build-msvc -G Ninja
cmake --build build-msvc

Either way you get dmodemd.exe, one file with no extra DLLs.

Running¶

Set your SIP account, then start the daemon:

set SIP_LOGIN=username:password@sip.example.com
dmodemd.exe -d1

Windows' firewall will ask once whether to let it use the network; it needs that for SIP calls.

Connecting a program to the modem¶

On Linux a program talks to D-Modem through a serial device. Windows has no such thing built in, so dmodemd.exe offers four ways instead:

Option	Use it for
`--tcp` (the default, `127.0.0.1:2323`)	terminal programs that can open a raw TCP connection, such as PuTTY or `telnet`
`--com COM5`	programs that want a COM port, using a virtual null-modem pair from com0com
`--pipe <name>`	a virtual machine's COM port (Hyper-V, VirtualBox, VMware), so an old guest system can dial out
`--driver auto`	D-Modem's own virtual modem driver (below)

The virtual modem driver¶

D-Modem includes a Windows driver that makes it appear in Device Manager as a real modem, "D-Modem Virtual Modem". Windows' own dial-up networking, Windows Fax and Scan, and any program that uses a modem can then use D-Modem directly, with no com0com needed.

dmodem-driver install dmodem.inf      (once, as an administrator)
dmodemd.exe --driver auto

It runs as a user-mode driver, so a bug in it cannot crash Windows. There is a version for Windows 10 and later and one for Windows 7, 8 and 8.1. It has not yet been tried on Windows itself.

USB modems¶

dmodemd.exe drives the SmartUSB56, the pico-serial sticks and the Agere USB modem (see Softmodem hardware). They need the generic WinUSB driver instead of their makers' drivers:

dmodem-driver usb dmodem-usb.inf      (once, as an administrator)
dmodemd.exe --usb list
dmodemd.exe --usb auto

On Windows 7 and 8, use libusbK or UsbDk instead of WinUSB.

What is not available on Windows¶

The Asterisk and FreeSWITCH modules, dmodem-ari, the PC modem chips (-a, which is Linux only), and the tests against other companies' modems.