I am trying to understand the vortex driver. I believe that I am not looking at the correct documentation. I read The following doc : PCI/EISA Bus-Master Adaptater Driver Technical Reference Members of the 3Com EtherLink III and Fast Etherlink families of adapters Manual Part Number 09-0681-001B The reason I believe there is a better doc is that the driver read info1 and info2 fields from the EEPROM and then does : if (vp->info1 & 0x8000) { vp->full_duplex = 1; if (print_info) printk(KERN_INFO "Full duplex capable\n"); } ... if (print_info) { printk(KERN_INFO " Enabling bus-master transmits and %s receives.\n", (vp->info2 & 1) ? "early" : "whole-frame" ); } But in my doc both these bits are marked 'reserved'. I understand that these bits could be defined in more recent chipset but in the doc I am looking at the full duplex capability is defined in another field in the EEPROM: Capabilities Word (offset 0x10) : supportsFullDuplex bit (bit 1) Christophe -- Christophe Barbé GnuPG FingerPrint: E0F6 FADF 2A5C F072 6AF8 F67A 8F45 2F1E D72C B41E Ce que l'on conçoit bien s'énonce clairement, Et les mots pour le dire arrivent aisément. Nicolas Boileau, L'Art poétique