The old hard-wired BT Voyager modem gives a speed check of 440 down and 240 up on a 512 connection - not bad I guess.
My 3Com wireless gives around 260 down and 140 up on the same connection.
3Com shows 'signal strength excellent' and 'Speed' varying between 36 and 54 Mbps.
What can I do to improve the wireless data rate, and should those figures be giving better please?
Going back to the original question, are you actually asking how to the the 3com to deliver the same ADSL speeds as the BT Voyager?
If so check you have the latest firmware in the 3Com.
The slowest point in most home networks linked to basic broadband now will the ADSL line, standard ethernet (wired) is 10 Mb/s or 100Mb/s on most modern PCs. WiFi a minimum of 1Mb/s with a degraded signal, so the theoretical 512kb/s down 256kb/s up is slow wrt the rest of the network.