This implementation adds pseudo terminal (PTY) support to tcpser, allowing you to use Hayes-compatible modem functionality through a PTY device instead of requiring a physical serial port.

The -P option has been added to create or use a pseudo terminal:

-P   pseudo terminal (PTY) - auto-create or specify device (e.g. /dev/pts/15)

# Create a PTY modem listening on default port 6400
./tcpser -P mymodem -s 38400

# Create a PTY modem with specific TCP port
./tcpser -P mymodem -s 38400 -p 2323

# Use a specific PTY device
./tcpser -P /dev/pts/15 -s 38400

# Use a specific PTY device with custom TCP port
./tcpser -P /dev/pts/20 -s 38400 -p 2323

# First modem on PTY, second on serial port
./tcpser -P modem1 -s 38400 -d /dev/ttyS0 -s 9600

1. Auto-Create Mode: When using -P with a name hint (e.g., -P mymodem), tcpser creates a pseudo terminal pair automatically
2. Specify Mode: When using -P with a device path (e.g., -P /dev/pts/15), tcpser opens the specified PTY device
3. Device Output: The PTY device name is displayed (e.g., Pseudo terminal device: /dev/pts/13)
4. Hayes Commands: Connect to the PTY device to send AT commands
5. Network Bridge: Commands like ATDT hostname:port establish TCP connections

# Connect to the PTY device (replace /dev/pts/13 with your device)
minicom -D /dev/pts/13 -b 38400

screen /dev/pts/13 38400

# For auto-created PTY, use the device shown in tcpser output
# For specified PTY, use the device you specified

# In one terminal, read responses
cat /dev/pts/15 &

# In another terminal, send commands
echo -e "AT\r" > /dev/pts/15
echo -e "ATDT example.com:23\r" > /dev/pts/15

# Create a PTY pair with socat for testing
socat -d -d pty,raw,echo=0 pty,raw,echo=0

# Use one of the PTY devices with tcpser
./tcpser -P /dev/pts/16 -s 38400

• AT - Basic attention command (should respond "OK")
• ATZ - Reset modem to default settings
• ATDT hostname:port - Dial/connect to a TCP host and port
• ATDT hostname - Connect to host on default port 23 (telnet)
• ATH - Hang up connection
• ATA - Answer incoming call
• +++ - Escape sequence to return to command mode

AT
OK

ATDT towel.blinkenlights.nl:23
CONNECT 38400

[Star Wars ASCII animation plays]

+++
OK

ATH
NO CARRIER

1. New Files:

   • src/pty.h - PTY interface definitions
   • src/pty.c - PTY implementation

2. Modified Files:

   • src/dce.h - Added PTY support to DCE configuration
   • src/dce.c - Integrated PTY functions into DCE layer
   • src/init.c - Added -P command line option
   • Makefile - Added PTY source files and -lutil library

• Automatic PTY Creation: Uses openpty() to create master/slave pair
• Control Line Simulation: Simulates DTR/DCD for compatibility
• Hayes Protocol: Full compatibility with existing Hayes command set
• Flow Control: Supports software flow control (XON/XOFF)
• Multi-modem: Can be combined with serial and IP232 modems

1. No Hardware Required: Works without physical serial ports
2. Container Friendly: Perfect for Docker/containerized environments
3. Testing: Ideal for development and testing scenarios
4. Retro Computing: Enables vintage systems to connect via modern networks
5. BBS Systems: Allows old BBS software to accept network connections

• Ensure you have permissions to create PTY devices
• Check that /dev/pts is mounted and accessible

• Verify the PTY device name in the tcpser output
• Ensure line endings are correct (use \r not \n)
• Check that the terminal application supports the baud rate

• Verify the target host and port are accessible
• Check firewall settings
• Ensure tcpser is listening on the correct port

The PTY support requires the util library:

make clean
make

On some systems, you may need to install development packages:

# Ubuntu/Debian
sudo apt-get install libutil-dev

# CentOS/RHEL
sudo yum install libutempter-devel