netmodem2irc

Revival of Dedrick Allen's NetModem/32 (32-bit FOSSIL Telnet server, 1997-2001) for modern Windows, with a portable, tested Pascal modem-emulation engine.

Status

38 test programs, 0 failures. Server, config, and FOSSIL bridge compile. Original CPL included.

Component	Target	Status
Engine (emulation core)	Any platform	✅ 38/38 tests pass
NMServer.exe	Win98 / NT	✅ Compiles (needs LCL to link)
NMConfig.exe	Win98 / NT	✅ Compiles (needs LCL to link)
NETMODEM.CPL	Win98 / NT	✅ Original Dedrick Allen binary (657KB)
netfossl.exe	DOS (i8086)	✅ Built — 179KB FOSSIL binary

Architecture

CPL (NETMODEM.CPL, original) or NMConfig.exe
    ↓ writes/reads registry
    HKLM\Software\Allen Software\NetModem
      ComportConfig   REG_BINARY (per-node: comport, baud, mode)
      IRQ             REG_DWORD
    ↓ IOCTL 03 (reload config, no reboot)

VxD Driver (NETMODEM.VXD on 9x) or com0com (on NT)
    ↑ reads registry at boot
    ↓ posts CM_* messages to server window

NMServer.exe
    ↑ IOCTL 08 (register window)
    ↓ reacts to CM_CONNECT/DISCONNECT/BREAK
    ↓ opens/closes TCP sockets via Synapse

FOSSIL bridge (netfossl.exe)
    ↑ FOSSIL INT 14h + fpcirc TCP/IP
    ↓ direct serial↔TCP relay (no Windows needed)

Configuration

The VxD reads config from the Windows registry. The CPL and NMConfig write the same keys. The server does NOT read config — the driver already has it.

HKLM\Software\Allen Software\NetModem
  ComportConfig   REG_BINARY   array of ComportStruct (22 bytes/node)
  IRQ             REG_DWORD    interrupt number (0 = none)

Per-node ComportStruct fields (matches original CPL 1:1):

Field            Size   Default        Description
Node             Byte   1              node slot
Enabled          Byte   1              node active
ComportNumber    Byte   3              virtual COM port (1-99)
szComportName    7      "COM3"         ASCII name
Emulation        Byte   1 (FOSSIL)     0=UART, 1=FOSSIL
Baudrate         Word   38400          300-115200 (14 rates)
Internetport     Word   23             TCP listen port
Baseaddress      Word   $03E8          I/O base address
Alwaysactive     Byte   0              keep node up without connection
Lockedbaudrate   Byte   1              lock baud rate
Managetimeslice  Byte   1              yield CPU when idle
Buffersize       Word   2048           RX/TX buffer (1024-8192)

Factory defaults written to registry on first run if no config exists. Connection targets come from AT dial commands (ATDT host:port), not config.

Repository layout

engine/         emulation engine — UART, FOSSIL, Telnet transport, AT commands,
                multinode, Synapse + named-pipe links, server bridge, seam
                protocol, TSR skeleton, per-node + global config
engine/test/    test suite (sh engine/test/run-tests.sh) — 38 tests
server/         NMServer — Lazarus GUI, Telnet server (was NETMODEM.EXE)
config/         NMConfig — Lazarus config app, all per-node + global settings
cpl/            Original CPL forms (decompiled DFMs for reference)
dos/            i8086 DOS FOSSIL↔TCP bridge (netfossl.exe, fpcirc cross-compile)
common/         NMVxD.pas — driver interface (IOCTL, CM_* messages, ComportStruct)
driver/src/     Dedrick's original 9x VxD source (MASM, experimental)
libs/synapse/   Ararat Synapse networking (modified-BSD, GPLv2-compatible)
history/        Dedrick's original distributions + NETMODEM.CPL binary
installer/      Inno Setup installer script (.iss)
docs/           active engineering docs, specs, bug reports
attic/          retired docs and files

Building

Requires fpc264irc r3.1+ (github.com/verta1878/fpc264irc).

FPCIRC=/path/to/fpc264irc ./build.sh          # build everything (tests + win32 + fossil)
FPCIRC=/path/to/fpc264irc ./build.sh tests     # engine tests only (38/38)
FPCIRC=/path/to/fpc264irc ./build.sh win32     # cross-compile Win32 binaries
FPCIRC=/path/to/fpc264irc ./build.sh fossil    # DOS FOSSIL binary
./build.sh resources                           # compile icon .rc → .res files
./build.sh clean                               # remove build artifacts
make clean                                     # same via Makefile

Win32 cross-compile

./build.sh win32 cross-compiles NMServer.exe and NMConfig.exe from Linux using fpc264irc ppc386 + Win32 LCL. Copies original NETMODEM.CPL to out/win32/. Output goes to out/win32/. Requires i686-w64-mingw32-windres for icon embedding (apt install binutils-mingw-w64-i686).

Icon resources

Original icons extracted from Dedrick's NETMODEM.CPL (14 icons, 36 bitmaps). Compiled via windres into .res files embedded in each binary:

server/resources/NMServer.rc   → server.ico
config/resources/NMConfig.rc   → mainicon.ico

DOS (netfossl.exe)

Requires fpc264irc r3.1+ with i8086 cross-compiler + OpenWatcom wlink:

FPCIRC=/path/to/fpc264irc ./build.sh fossil

Engine (tested)

• NM_UART16550 — 16550 UART emulation
• NM_Fossil — FOSSIL INT 14h (init signature $1954)
• NetTransport — Telnet transport, IAC/BINARY, binary-safe
• NM_ATCommand — Hayes AT, ATDT dial
• NM_Node — per-node object + multinode manager (comports 3-99)
• NM_SynapseLink — real Synapse TCP socket link
• NM_NamedPipeLink — named-pipe link (virtual-COM driver seam)
• NM_ServerBridge — wires engine to server's CM_* + TIOStruct IO
• NM_SeamProtocol / NM_SeamSender — driver↔server framed protocol
• NM_TSR — FOSSIL TSR resident-program skeleton
• NM_Config / NM_ConfigApply — per-node config (comport/baud/mode)
• NM_DefaultConfig — factory defaults + registry read/write
• NM_GlobalConfig — server-level settings (logging, network, display files, features)
• NM_Listserv — BBS Listserv directory registration
• NM_AutoNews — periodic news/announcement broadcast
• NM_FossilDriver — INT 14h register-frame dispatch (testable)

Platforms

Platform	Driver	Transport
Windows 95/98/ME	NETMODEM.VXD (Dedrick's original)	WinSock via Synapse
Windows NT/2K/XP+	com0com virtual COM port	WinSock via Synapse
DOS (real mode)	FOSSIL INT 14h (fossil_dos.pas)	fpcirc TCP/IP (BSD sockets)

Credits

Original NetModem/32: Dedrick Allen (mag69), 1997-2001. Allen Software. Released under GNU General Public License v2.

Revival: Antonio Rico (Reapern66 / verta1878). Built with fpc264irc r3.1+ (github.com/verta1878/fpc264irc).

License

GNU General Public License v2 — see LICENSE.

Roadmap

Features from Dedrick's original CPL that were designed but never finished (NetModem/32 v2.0 was alpha when development stopped):

• Auto-News — periodic SMTP announcement broadcast ("BBS is online"). CPL has the checkbox + interval setting. Engine unit ready (NM_AutoNews), needs SMTP send via Synapse smtpsend.pas (same license, drop-in).

• BBS Listserv — SMTP mailing list registration. CPL has the full info form (BBS Name, Software, Speed, Hostname, IP, Port, Comment). Engine unit ready (NM_Listserv), needs Synapse smtpsend.pas + mimemess.pas + mimepart.pas for SMTP subscribe/announce. Both features were designed by Dedrick but never implemented — the CPL UI exists, the backend doesn't. Synapse units needed are modified-BSD, same license as our existing copy.

• Phonebook — AT dial directory (ATDS/AT&Z). Design doc done

• Blocking/Forwarding — address-based connection filtering. CPL has TForm6 (address entry with wildcards) and NETMODEM.BLK file. Not implemented.

• Full CPL GUI rebuild — using Dedrick's original NETMODEM.CPL binary. 6 decompiled DFM forms preserved in cpl/original_forms/ for reference.

• Live Telnet connection — AT command parser exists, nothing dials yet.

Installer

Inno Setup script at installer/netmodem2irc.iss. Build the Win32 binaries first, then open the .iss in Inno Setup Compiler to produce netmodem2irc-setup.exe. Requires Inno Setup 5.5+ (Win98) or 6.x (Win7+). See installer/README.md for details.