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        MIDI-OX >> Questions and Discussion >> Sending/Receiving SysEX by Port ID
        
(Message started by: Lynn on Apr 10^th, 2005, 1:29pm)

Title: Sending/Receiving SysEX by Port ID
Post by Lynn on Apr 10^th, 2005, 1:29pm

I have been writing MIDI-OX scripts for years, and I was very happy when the ability to direct regular midi output to a SPECIFIC port became available.

Unfortunately, it seems that the port from which SysEx input arrives is not passed to the script.

Worse, the documentation on SendSysExString or SendSysExFile shows no parameter for specifying which OUTPUT port to send the SysEx data. In fact, the doc says explicitly that the SysEx data is sent to "all ports attached by an instance".

Is there no way to direct SysEx output to a specific device? I have sevenal devices attached: Roland 8850, Roland 88VL, Roland D-110, Sound Blaster Live -- and all of them have unique SysEx specifications! How am I to keep from sending the same SysEx messages to ALL of them at once?

Title: Re: Sending/Receiving SysEX by Port ID
Post by Peter L Jones on Apr 10^th, 2005, 2:57pm

on 04/10/05 at 13:29:49, Lynn wrote:

How am I to keep from sending the same SysEx messages to ALL of them at once?

SysEx is designed to work with multiple devices on a single cable. So long as each device knows its SysEx ID and disregards SysEx messages destined for other devices, you're okay. Devices that don't do this aren't fully MIDI-compliant.

Some devices extend this by adding an "instance ID" of some sort to the SysEx message. That lets you target a specific instance of a specific device.

So it should "just work"... (Okay, I guess you're sending SysEx down cables you didn't need to...)

<edit>
Oh... Uh, I guess there may be some "generic" SysEx messages a manufacturer like Roland might use on all their devices - like, say, reverb parameters or something... That could cause problems... Still, it's a bit naughty if they do...
</edit>

Title: Re: Sending/Receiving SysEX by Port ID
Post by Jamie OConnell on Apr 19^th, 2005, 2:09pm

As Peter mentioned, SysEx has the target device model and manufacturer encoded in it, by definition, so it is safe to send to any device connected.