many serial devices sending to one device - problem

I have a big problem (for me at least), and I’m hoping someone can help me out. I have an internal system used by over 1,000 people in our company which a major component of is being changed tomorrow morning, and if I don’t figure this out today, things could get real ugly. I have a scenario whereby I have a messaging keyboard which sends data to a device via an RS-232 port. This device then transmits this message to a wireless device. The problem I’m running into is that the transmitting device only has one RS-232 port, so can only handle one messaging keyboard. Changing the transmitting device will require changing an entire system, which will cost a lot and take weeks of programming, neither of which I have. I have a Portserver TS 8 which I figure I can handle the problem with. The idea is that I have 6 keyboards that are plugged into the Portserver (ports 1-6), the transmitting device is on port 8. Anything that comes in on ports 1-6, gets sent over to port 8 to the transmitter. For this I used an IA setup. This works good for one keyboard. Any more than one works fine, until there are two keyboards that try to transmit at the same time. If both messages from the keyboards are received at the same, exact time, the transmitting device has a blue and purple cow and doesn’t receive either message. Both keyboards will eventually time out and you try again. If one gets there before the other, the first one goes through. On the transmitting device, I can see the second one trying to get through but it doesn’t. The keyboard eventually times out and you try again and it will go through fine. This could probably be lived with if there were only 2 keyboards being used, but I need to have 10 eventually, each sending an average of 500 messages a day. So this will be rather painful. I guess what I need is some way to queue/buffer all the messages coming in on the various ports and send them one by one to the transmitting device on port 8. I’ve been banging my head against the wall for days and it’s resulted in nothing but splinters in the brain. Hoping someone has run into this before.

I believe you opened a case in Tech Support and that we gave you a solution for this using a custom protocol setup in the IA engine. Here was our response:

Yes, this should work as long as the TAP protocol is strictly half-duplex, so 1 master poll returns 1 slave response.

If this is a protocol where the master talks & keeps kicking the slave until it answers, then it wouldn’t work. Or if the master sends 1 request and the slave sends many responses until done.

Also, timing may be a factor. Please see the following article to see if latency might be a problem:

That application note was written for another product, but applies to using the TS8 in IA mode with a custom protocol as well.