Wireless problems -- talked to ISP

I had a word with Eircom today about the fact that we seem to be losing wireless now and again. However, we can get it back very easily by changing the wireless privacy from WEP-manual to WEP-automatic.
First, I asked how does it go back to manual from auto. Of, course, this occurrs everytime I reset the router which I tend to do whenever there's a problem.
However, I forgiot to ask why should manual give rise to a loss of wireless.
He also pointed out that reseting would also bring the default chanel back to 7. I had set it to 1 some time ago but never noticed that it had gone back to 7.
He then asked if we had any new equipment that was generating a signal in the wireless region (2.4 GHz).
I told him we had recently revitalised a cordless phone and he said that most of the problems he comes across are due to cordless phhones interfering with wireless internet.
He then suggested that selecting chanel 13 has the best chance of minimal interference from a cordless phone (which, apparently can change frequency as they hunt for an optimal signal).
So, I changed from chanel 7 to 13 and the frequency changed from 2.442 GHz to 2.472 GHz. I'll leave this for a week or two to see if it's any better or not.