Extron RS-232 Control Guide: SIS Commands for Switchers and Displays
Extron's Simple Instruction Set (SIS) is one of the most integrator-friendly RS-232 protocols in commercial AV. Unlike Panasonic's STX/ETX framing or Sony's binary HEX protocol, Extron SIS commands are plain ASCII text you can type directly from a keyboard. Once you learn a handful of commands, they work across most Extron products.
Serial Port Settings
| Parameter | Value |
| Baud Rate | 9600 |
| Data Bits | 8 |
| Parity | None |
| Stop Bits | 1 |
| Flow Control | None |
| Cable Type | Straight-through |
| Terminator | CR (0x0D) |
SIS Command Format
Extron SIS commands are plain ASCII with a carriage return terminator. The device responds with a status message followed by CR+LF. If an invalid command is sent, Extron returns an error code like E01 (invalid input number) or E13 (invalid command).
Power Control
| Function | Command |
| Power On | `< + CR` |
| Power Off | `> + CR` |
| Query Status | `I + CR` |
Input Switching
Single-output switchers:
| Function | Command |
| Switch to Input 1 | `1! + CR` |
| Switch to Input 2 | `2! + CR` |
| Query Current Input | `I + CR` |
Matrix switchers (tie input to output):
| Function | Command |
| Tie Input 1 to Output 1 | `1*1! + CR` |
| Tie Input 2 to Output 3 | `2*3! + CR` |
| Tie Input 1 to All Outputs | `1*0! + CR` |
| Disconnect Output 2 | `0*2! + CR` |
| Query All Ties | `0LS + CR` |
Video Mute
| Function | Command |
| Video Mute On | `B + CR` |
| Video Mute Off | `b + CR` (lowercase) |
| Audio Mute On | `Z + CR` |
| Audio Mute Off | `z + CR` (lowercase) |
Crestron SIMPL+ Example
```
STRING_PARAMETER SP_PowerOn[3] = "<\x0D";
STRING_PARAMETER SP_PowerOff[3] = ">\x0D";
STRING_PARAMETER SP_Input1[4] = "1!\x0D";
STRING_PARAMETER SP_Input2[4] = "2!\x0D";
DIGITAL_INPUT PowerOn, PowerOff, Input1, Input2;
STRING_OUTPUT TX$;
PUSH PowerOn { TX$ = SP_PowerOn; }
PUSH PowerOff { TX$ = SP_PowerOff; }
PUSH Input1 { TX$ = SP_Input1; }
PUSH Input2 { TX$ = SP_Input2; }
```
Common Mistakes
- ▸Forgetting the CR terminator — without it the device waits and never executes
- ▸Using wrong cable — Extron uses straight-through, not null modem
- ▸Not reading the response — Extron ACKs every command. Send too fast and the buffer fills, dropping commands silently
- ▸Front panel lockout — some Extron products have a lock mode that also blocks RS-232
Related Guides
- ▸Panasonic Projector RS-232 Commands
- ▸[Extron RS-232 Control Guide — SIS Protocol]- Sony BRAVIA Professional RS-232 Commands
- ▸NEC Display RS-232 Commands
- ▸Kramer Switcher RS-232 Commands — Protocol 2000 & 3000
- ▸Crestron SIMPL+ Serial Control Guide
- ▸Biamp Tesira RS-232 and Telnet Control
- ▸QSC Q-SYS External Control Protocol
- ▸AMX NetLinx Serial Control Guide
- ▸RS-232 vs IP Control in Commercial AV
- ▸Crestron vs AMX vs Extron: Control System Comparison
Free RS-232 Tools
Baud rate reference, device settings table, terminator guide, and DB9 pinout — all free, no signup required.
Generate RS-232 Commands Instantly
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