By Rick Escobar - TOA Product Support Assistant Manager

One issue we hear from time to time is that "My Brand X" controller cannot control a TOA product by sending RS-232 commands. For this example, let's refer to a 9000M2 series Matrix / Mixer Amplifier (for you references download this document "9000M2 RS232C Protocol Manual" by clicking here).

We'll skip the low level detail and get to the point on how to make your control surface work for you. The 9000M2 is looking for a hexadecimal string that it will read then react to the instructions sent. Here is an excerpt from the "9000M2 RS232C Protocol Manual":
5.5 Power ON/OFF
This command performs ON/OFF setting of the power switch of the 9000M2 Series
Amplifier. 9000M2 Series Amplifier responds with the same data as that received.
F4H, 01H, < ON/OFF >
Example 1: Setting the power switch to OFF
F4H, 01H, 00H
Example 2: Setting the power switch to ON.
F4H, 01H, 01H

A common misconception is that the H is required in the command string. However, in this case it's just noting that F4 is going to be a hexadecimal number. There is no standard for different control manufactures or terminal programs. So the first step is to understand how the device you are working with is going to want this string formatted. All of these examples could be valid to power the 9000M2 off:
\xF4\x01\x00
01#00
[F4][01][00]
And so forth.

The best recommendation would be to have the ability to cross check a string with a Terminal Program. This way if the hardware controller does not work but the software terminal does, then you have isolated the issue most likely to how the device in question wants the string formatted. A key word search on the internet for "RS-232 terminal emulator" will turn up several programs that provide you the ability to send RS-232 to your TOA product.

Good Luck and Happy RS-232 Programming!