A mechanism detects cable length in a storage subsystem with wide ports. The mechanism uses in-situ bidirectional cable wrapping for determining different cable lengths. The mechanism under-margins transmitter output to failure for each external port and even for each PHY within a wide port. Based on the transition point from “good” wrap to “bad” wrap, the cable length may be determined. The transition point identifies if the cable is long or short, at which point the optimum tuning parameters can accordingly be set. A calibration mechanism calibrates the high speed transmitter/receiver pair characteristics, and, thus, optimizes the transmission performance between subsystems. The calibration mechanism mitigates the need for frequent error correction and does not incur the performance degradation associated with error correction techniques.