Multiple radios via USB programming leads

[Rob_Brookes]

Recently reported is what might be a problem to teams wishing to use multiple radios with MRMap. This is an option where remote repeater sites for example, can be controlled over a radio link using radios on different link channels. All these radios are capable of having GPS data taken off them and so complete area coverage as far as GPS tracking is concerned, is achieved regardless of whether that repeater is being used for voice or not.

As most modern computers come with no serial ports but lots of USB ones, the obvious choice for leads to accomplish this task is the USB to serial one produced by Simoco. Unfortunately as this was designed to program only one radio at a time, it appears that the driver can only accept a single instance of a lead being plugged into the machine. It won't allocate multiple comm ports to multiple leads and so you can extract GPS data from one radio only.

The solution is fairly simple in the case of a desktop computer, fit multiple PCI serial cards. This is what I've done at Langdale's base and it works fine. This doesn't work at all where laptops are concerned however as fitting internal cards usually isn't possible. PCMCIA or PCMCIA Express cards might get over this restriction but haven't been tried.

No additional information is available on this as yet but TMC have been asked for their comments.

It has to be stressed that this is in no way a fault. Only one radio is usually programmed at a time and this is the primary design function of the lead in question. It's us who are expanding it's use somewhat in needing more than one lead to be connected.

[David_Binks]

This is something that we have suspected for a while. Basically it seems that the windows driver that has been written for these leads is not thread safe. I don't know if Simoco wrote the driver or if it was a third party generic driver, but either way I think that it could probably be sorted relatively easily.

The alternative solution (which we use) is to use the old style radio to 9 way D type leads and then use a Serial to USB converter. I don't know how much a serial card is for a PC, but the USB to serial leads are about £10 each.

Dave.

[Rob_Brookes]

Well, I successfully managed to get that one wrong! Whilst Dave's reply is still probably correct (he knows about these things), the reply I got from TMC in Oz included a screen shot of two instances of the programming software programming two radios simultaineously via two USB programming leads. As far as their own software is concerned, multiple USB programming leads will work. I will try and gather enough USB leads to allow me to test it myself but it seems I was wrong on this one.

[David_Binks]

It seems that it is "Process safe", but not "thread safe". I.e you can use lots of leads providing you only use one lead per application.
MRMap uses several leads within one process, and within that process it uses these leads simultaneously in different threads.

To complicate things further, the original SRMDRV.DLL (the bit of TMC Simoco code that handled talking to the serial lead drivers and then onto the radios) was also not thread safe. They very kindly gave me the source code for this so that I could make this thread safe, and have done so, but this bit of code still has to talk to the serial lead drivers.

Now the RS232 to USB leads that we use with the old radio leads have a driver that is thread safe, but the driver for the new lead seems not to be. In my opinion I think that it should be!

Rob, if you pass this onto TMC I think they will understand what I am saying! If not then get them to contact me direct and I'll summarise the outcome

Dave.