Epson Projector RS232 Baud Rate and Settings: Setup Guide

An Epson projector's RS-232C port speaks ESC/VP21 at 9600 bps, 8 data bits, no parity, 1 stop bit and no flow control. Typing those five values into a controller is the easy part. Whether the link actually works is decided by four other settings: the menu option that routes commands to the serial or USB port, an HDBaseT option that can switch the projector's own RS-232C port off, the standby configuration that limits which commands are accepted, and how long your controller waits between commands. This guide goes through them in the order you meet them during commissioning. For the command list itself, see the Epson ESC/VP21 command reference.

The five serial parameters, and what "Default" means

Epson's ESC/VP21 Command User's Guide lists the communication condition in its appendix, under the serial connection section:

The newer online User's Guide for the EB-L690/L695/L790/L890/L895 series gives the same data length, parity, stop bit and flow control, but words the rate differently: "Default baud rate setting: 9600 bps".

That one word matters. "Default" implies the rate is adjustable on at least some models, yet neither document lists the alternative rates or names the menu item where the rate would be changed. Not found in Epson's official documentation. The practical rule that follows: configure your controller for 9600, and if a projector that someone else has already set up refuses to answer at 9600, go to that exact model's own manual rather than cycling through rates at random. We do not publish a list of other Epson baud rates, because the vendor material behind this page does not contain one.

The guide also notes that because ESC/VP21 command codes are plain ASCII, you can control a projector from a PC with an ordinary terminal emulator. That makes a terminal program set to the five values above the right first test tool, before any control system is involved.

On the connector: the ESC/VP21 guide says D-Sub 9-pin, and the EB-L690 series guide specifies a D-Sub 9-pin male port with a crossover (null modem) cable. Some newer models differ; the EB-PU2220B/EB-PU2120W User's Guide lists a Mini D-Sub 9-pin male RS-232C port. Pin-by-pin wiring is covered in the Epson RS232 pinout guide.

Step 1: Tell the projector which port to listen on

Having the cable plugged in is not enough on older models. For the models in the guide's serial connection list, the instruction is: "Select RS-232C at Advanced Setting of the Menu."

For newer models, the menu path that enables serial control is not given in the documents this page is based on. Not found in Epson's official documentation; check the model's own User's Guide.

USB control uses a different menu option, and it varies by model family. Summarised from the guide's USB connection section:

Note that in the guide, Link 21L appears only in the USB connection section. It is not described as a serial-port option, so selecting it will not be the fix for a dead RS-232C port.

USB control also needs the EPSON USB COM Driver on the computer. Once it is installed and the USB cable is connected, a COM port appears in Device Manager as "EPSON COM Emulation port (COMn)". The guide names two installers: EMPUSBSetup.exe for the 600/800/810/811/820/720/730/520/73/53/74/54/735 group, and EMPUSB2Setup.exe for 7800/7850, 8300/9300 and a long list of later models. The guide states the 9600/8/N/1 condition under the serial connection section only; whether the emulated USB port expects the same settings is not found in Epson's official documentation.

Step 2: Make sure HDBaseT has not taken over the port

On models with HDBaseT, the EB-PU2220B/EB-PU2120W User's Guide describes a setting at Extended > HDBaseT > Control Communications. Setting it to On enables the Ethernet and serial ports on the connected HDBaseT transmitter or switcher, and disables the projector's own LAN, RS-232C and Remote ports.

The field consequence is a projector that ignores a perfectly wired serial cable with perfectly matched parameters. Either run your controller's serial line to the transmitter or switcher, or set Control Communications to Off and use the projector's port. The serial settings of the transmitter's port are not stated in Epson's manual. Not found in Epson's official documentation.

Step 3: Know which standby configuration you are in

The ESC/VP21 guide distinguishes two standby configurations, "network on" and "network off", and the rules differ:

• Standby with network on: the first command can be sent at any time; subsequent commands should wait for the colon.

• Any other standby case: only PWR ON can be sent at any time.

• Power on: every command should wait for the colon returned by the previous one.

What the projector accepts in standby also depends on the model. The guide's notes give three examples: EMP-61/81/830/835/740/745/821/828 accept only PWR ON, PWR?, LAMP? and the null command; EMP-7800/7850 accept only PWR ON, PWR?, SOURCE? and the null command; EMP-8300/9300 accept PWR ON, SOURCE xx, PWR?, SOURCE? and the null command. Everything else returns ERR.

PWR? tells you which configuration a projector is in, on the models that report it: 00 means standby with network off, 04 means standby with network on. The guide lists which models return each value, so check that your model appears in the relevant row.

Newer models document a related setting. In the EB-PU2220B/EB-PU2120W User's Guide, Extended > Standby Mode set to Communication On lets you monitor and control the projector over a network while it is in standby, including through the web browser interface. It has three preconditions:

• A/V Output must first be set to While Projecting.

• Auto Power On must be Off or Computer.

• USB Power must be On While Projecting.

Read those together with the A/V Settings entry in the same manual: A/V Output = Always On keeps audio and video output alive in standby. Since Communication On requires While Projecting, the manual's wording means you cannot have both at once. The manual describes Communication On in terms of network monitoring; whether it changes what the serial port accepts in standby, or maps onto the older guide's "network on", is not found in Epson's official documentation.

Step 4: Pace commands the way the protocol expects

ESC/VP21 flow control is the colon: the projector returns : when it has finished a command and is ready for the next. If your controller cannot wait for the colon, the guide says to wait the command's execution time instead. What its table and notes state:

• PWR ON: 40 seconds. The lamp is ignited up to three times; the colon comes back within 40, 70 or 100 seconds if the first, second or third attempt succeeds. Three failures means a lamp failure.

• PWR OFF and SOURCE have separate rows for specific older model groups (20 and 25 seconds respectively); all other commands range from 130 down to 3 seconds depending on the model. Read your model's row in the table; do not apply one figure to every projector.

• With a stable input sync signal, the colon returns within 5 seconds; an unstable signal can take longer.

• Projectors execute PWR OFF only after they have started completely.

• On 7800/7850/8300/9300 in the network-off standby configuration, after PWR OFF wait 10 seconds beyond the colon before the next command.

Commands useful during setup, with the bytes each one puts on the wire:

Null command   0D                         -> reply  3A  (":")
PWR ON<CR>     50 57 52 20 4F 4E 0D
PWR?<CR>       50 57 52 3F 0D
ERR?<CR>       45 52 52 3F 0D
Invalid command reply:  45 52 52 0D 3A   ("ERR" <CR> ":")

Verification: from-vendor-doc — per Epson's ESC/VP21 Command User's Guide; not tested against real hardware in this repo.

Field pitfalls: the check order

When a new Epson link does not respond, work through it in this order.

• Send a null command from a terminal emulator. A bare carriage return should return a colon; Epson documents the null command as a way to confirm that the projector is in operation. A colon coming back also means bytes are travelling in both directions, so the cable, the COM port and the serial parameters are all doing their job.

• No colon at all? Check, in order: the serial option in the menu (Step 1); HDBaseT Control Communications (Step 2); the cable type and connector (crossover, and D-Sub versus Mini D-Sub); and, for USB, that you opened the "EPSON COM Emulation port" number Device Manager shows. Also rule out an abnormal state: during a lamp failure or abnormal high temperature the projector neither executes commands nor returns a colon. On some models (6100/6000, 1715/1710/1705/1700, 1815/1810, S5/X5/83/822 and later) PWR ON is accepted again only after the abnormal state has lasted 130 seconds. A warning indicator alone, such as a high temperature warning, does not stop commands from executing.

• ERR instead of a colon? The guide gives three causes: the command is outside the standby subset for that model, the format is wrong, or the projector is not yet ready to reply.

• Works from a terminal, fails from the controller? Check pacing next. A person typing at a terminal naturally sees the colon before typing the next command; a controller sending a sequence does not wait for it unless it is configured to, and the protocol rules in Step 4 then apply. More on this in the Epson RS232 troubleshooting guide.

SoftControl import snippet

In SoftControl, an Epson serial command uses protocol: serial, with the COM port name in targetIpOrCom and the baud rate in portOrBaud. SoftControl's serial driver fixes 8 data bits, 1 stop bit and no parity, and has no flow-control field, so the one value you choose is the baud rate: 9600. For USB control, put the COM number of the "EPSON COM Emulation port" in targetIpOrCom.

Two behaviours shape the configuration:

• SoftControl does not add a carriage return on serial. Put \r at the end of commandText in text format, or end with 0D in hex format.

• SoftControl does not read the reply or wait for the colon on serial. It writes the bytes, pauses 50 ms, and moves on. Any ERR the projector returns is not surfaced. Pacing must therefore come from delayMs, which is the time SoftControl waits before running that command in a sequence. The gap belongs on the second command, not the first.

A power-on-then-select-input sequence:

name: Projector power on
protocol: serial
targetIpOrCom: COM1
portOrBaud: 9600
payloadFormat: text
commandText: PWR ON\r
delayMs: 0

name: Projector input select
protocol: serial
targetIpOrCom: COM1
portOrBaud: 9600
payloadFormat: text
commandText: SOURCE 30\r
delayMs: 40000

The 40000 ms comes from the 40-second PWR ON execution time. If the lamp needs a second or third ignition attempt, the colon arrives at 70 or 100 seconds, so a SOURCE sent at 40 seconds would arrive before the projector is ready; use 100000 if you want to cover the worst documented case. The meaning of 30 itself varies by model: in Epson's 2008 revision of the guide it is INPUT3 (DVI-D) on some models and INPUT3 (HDMI) on others. Replace it with your model's code.

The same power-on command in hex format, equivalent byte for byte:

name: Projector power on (hex)
protocol: serial
targetIpOrCom: COM1
portOrBaud: 9600
payloadFormat: hex
commandText: 50 57 52 20 4F 4E 0D

Verification: from-vendor-doc — command strings and timing per Epson's ESC/VP21 Command User's Guide; not tested against real hardware in this repo.

What to check before touching the baud rate

A wrong serial parameter shows up as a missing colon on the null-command test, but so does a serial option that was never selected in the menu or an HDBaseT setting that has disabled the projector's own port. A standby configuration that rejects the command you tested with, or a controller that sends the next command before the projector has answered the last one, only shows up once real commands are sent. Epson's documentation gives no alternative baud rates to try, so rule out those four causes first.