Dedicated differential output buffers eliminate the need for external resistor networks on the transmit side of RSDS, PPDS, and the general purpose LVDS communications. This enhancement reduces board space and eases PCB routing in many high volume display column driver applications. The Cyclone® III allows selection of 25 Ω or 50 Ω series termination values. These values can be calibrated at power up before going into user mode. A periodic user mode calibration feature may be offered after device characterization. Adjustable slew rates can improve signal integrity by slowing down edge rates on non-performance critical I/O pins. This feature was not available in Cyclone® II devices.