With uncompromising standards, the 4te is engineered throughout to withstand even the most punishing portable applications, including multiple 6 ft drops to concrete. The 4te prints outstanding quality 4-inch receipts, proof of deliveries, labels, and invoices.The 4t comes with Serial and IrDA communication. The 4te is every bit as rugged as the 4t but it offers enhanced processing speeds (10 times faster), greater memory capacity, USB connectivity power status lights, external charging, and optional Bluetooth and 802.11b/g wireless connectivity.communication.