Hi Tony,
It is worth finding out the logon details to the Extricom kit, the latest firmware has a number of enhancements around client support, but failing that you may want to check a few things:
Power save mode, the wireless card may be set to save power, this means it goes to sleep when not in use and can lead to long ping times as the card has to wake up. I would suggest you select maximum performance and minimum power save.
Roaming aggression, some client cards allow this to be configured, with the Extricom system there is no roaming involved so you can minimise the time the client spends looking for better options.
There are other things you can try, but I would try these first as they are simple enough. If you do not have the password for the Extricom switch you could try the default which is admin and Switch1, you will need to access the box with https://x.x.x.x, if that does not work then re-post and we can try some other ways in.
Regards
Phil