Well, I have to admit at least I’m getting replies from Belkin, but I’m not really getting anywhere.

As a précis, it seems that the router cannot support full sized Ethernet MTUs (1500) in 802.11b mode. 802.11n seems to work fine with standard MTU sizes – I haven’t yet tried the 802.11g mode.

If anyone can decipher the latest reply, a small prize will be yours – or rather, if you can tell me that they’re not talking absolute rubbish:

Alex, the MTU is nothing but the Maximum Transmission unit which is used for the rate of data transfer. Usually most of the ISP’s or the programs use the MTU as 1400 by default. If a particular pc has issue in transferring files or connecting to some websites, this might be the issue with the MTU settings on the router/computer, since there is no proper data transfer.

In your issue, the Pre N card works fine even without changing the MTU size (before changing the MTU). So the issue is only with the non-Belkin wireless cards which are running at 11 mbps speed. May be this wireless card is not able to transfer the files when MTU is set to 1500 but at the same time the pre N card works at 1500. So the MTU depends upon the computer. Some computers work at 1400 and the other at 1500 and third may be at 1100.

Apparently, they’re passing it onto their research team to investigate, but I don’t hold out much hope (although I said that about getting any sort of reply). You will, of course, be the first to know when I do.