Xircom Inc, Woodland Hills, California has extended its external adaptor range for linking portables to local nets to include support for 16Mbps Token Rings. It is switchable between 4Mbps and 16Mbps and attaches to any MS-DOS portable computer via the parallel port. Xircom has struck a deal with Chalfont St Giles, Buckinghamshire-based Madge Networks Ltd, to incorporate Madge’s SmartRing software into the adaptor. Xircom says the advantages are reduced memory requirements on the portable; SmartRIng also includes an interface for IBM’s LAN Support program, eliminating the need to buy it separately. The 16Mbps Token Ring adaptor is $900.