diff --git a/README.md b/README.md
index fe25901..817b9ac 100644
--- a/README.md
+++ b/README.md
@@ -4,11 +4,12 @@ FastMCP server for serial port access via Model Context Protocol.
 
 ## Features
 
-- **Tools** for serial port control (open, close, write, configure)
-- **Dynamic Resources** for reading data (`serial://{port}/data`)
-- Full pyserial support (baudrate, parity, stop bits, etc.)
-- Multiple concurrent port connections
-- Raw byte and text modes
+- **RS-232 Mode**: Full modem control (RTS, DTR, CTS, DSR, RI, CD)
+- **RS-485 Mode**: Half-duplex bus communication with auto direction control
+- **File Transfer**: X/Y/ZMODEM protocols for reliable file transfers
+- **Auto-baud Detection**: Smart detection using 0x55 sync pattern analysis
+- **Dynamic Resources**: Read data via `serial://{port}/data`
+- Full pyserial support (baudrate, parity, stop bits, flow control)
 
 ## Installation
 
@@ -27,20 +28,67 @@ uv pip install mcserial
 claude mcp add mcserial "uvx mcserial"
 ```
 
+## Modes
+
+Ports open in **RS-232 mode** by default. Switch with `set_port_mode()`:
+
+| Mode | Use Case | Tools |
+|------|----------|-------|
+| RS-232 | Point-to-point serial | `get_modem_lines`, `set_modem_lines`, `pulse_line`, `send_break` |
+| RS-485 | Multi-drop bus (Modbus) | `set_rs485_mode`, `rs485_transact`, `rs485_scan_addresses` |
+
 ## Tools
 
+### Common (both modes)
+
 | Tool | Description |
 |------|-------------|
 | `list_serial_ports` | Discover available serial ports |
-| `open_serial_port` | Open a connection with config |
+| `open_serial_port` | Open connection (auto-detects baud if not specified) |
 | `close_serial_port` | Close a connection |
+| `set_port_mode` | Switch between RS-232 and RS-485 modes |
 | `write_serial` | Send text data |
 | `write_serial_bytes` | Send raw bytes |
 | `read_serial` | Read available data |
 | `read_serial_line` | Read until newline |
+| `read_until` | Read until custom terminator |
 | `configure_serial` | Change port settings |
 | `flush_serial` | Clear buffers |
-| `get_connection_status` | List open connections |
+| `get_connection_status` | List open connections with mode |
+| `detect_baud_rate` | Auto-detect baud rate |
+
+### RS-232 Mode
+
+| Tool | Description |
+|------|-------------|
+| `get_modem_lines` | Read CTS, DSR, RI, CD, RTS, DTR states |
+| `set_modem_lines` | Control RTS and DTR outputs |
+| `pulse_line` | Pulse RTS/DTR for reset sequences |
+| `send_break` | Send timed break signal |
+| `set_break_condition` | Hold/release break state |
+
+### RS-485 Mode
+
+| Tool | Description |
+|------|-------------|
+| `set_rs485_mode` | Configure hardware RS-485 (DE/RE control) |
+| `check_rs485_support` | Detect hardware RS-485 capability |
+| `rs485_transact` | Send/receive with automatic turnaround |
+| `rs485_scan_addresses` | Scan bus for responding devices |
+
+### File Transfer
+
+| Tool | Description |
+|------|-------------|
+| `file_transfer_send` | Send file via XMODEM/YMODEM/ZMODEM |
+| `file_transfer_receive` | Receive file via XMODEM/YMODEM/ZMODEM |
+| `file_transfer_send_batch` | Send multiple files (YMODEM/ZMODEM) |
+
+**Protocols:**
+- `xmodem` - 128-byte blocks, simple (1977)
+- `xmodem1k` - 1024-byte blocks
+- `ymodem` - Batch mode with filename/size
+- `zmodem` - Streaming, auto-resume (recommended)
 
 ## Resources
 
@@ -48,7 +96,7 @@ claude mcp add mcserial "uvx mcserial"
 |-----|-------------|
 | `serial://ports` | List available ports |
 | `serial://{port}/data` | Read data from open port |
-| `serial://{port}/status` | Port configuration info |
+| `serial://{port}/status` | Port config and mode |
 | `serial://{port}/raw` | Read as hex dump |
 
 ## Environment Variables
@@ -59,16 +107,34 @@ claude mcp add mcserial "uvx mcserial"
 | `MCSERIAL_DEFAULT_TIMEOUT` | 1.0 | Read timeout (seconds) |
 | `MCSERIAL_MAX_CONNECTIONS` | 10 | Max concurrent ports |
 
-## Example Workflow
+## Example Workflows
+
+### Basic RS-232
 
 ```
-1. list_serial_ports → find /dev/ttyUSB0
-2. open_serial_port(port="/dev/ttyUSB0", baudrate=115200)
+1. list_serial_ports() → find /dev/ttyUSB0
+2. open_serial_port(port="/dev/ttyUSB0")  # auto-detects baud
 3. write_serial(port="/dev/ttyUSB0", data="AT\r\n")
 4. Read resource: serial:///dev/ttyUSB0/data
 5. close_serial_port(port="/dev/ttyUSB0")
 ```
 
+### RS-485 Modbus
+
+```
+1. open_serial_port(port="/dev/ttyUSB0", baudrate=9600)
+2. set_port_mode(port="/dev/ttyUSB0", mode="rs485")
+3. rs485_scan_addresses(port="/dev/ttyUSB0")  # discover devices
+4. rs485_transact(port="/dev/ttyUSB0", data="\x01\x03...")
+```
+
+### File Transfer
+
+```
+1. open_serial_port(port="/dev/ttyUSB0", baudrate=115200)
+2. file_transfer_send(port="/dev/ttyUSB0", file_path="firmware.bin")
+```
+
 ## License
 
 MIT