- CJ1 CPU Bus Unit, Ether Cat Slave Unit, Communications cable STP (shielded twisted-pair) cable of category 5 or higher with double shielding,Comunications Functions Refreshing methods Free-Run Mode PDO data sizes TxPDO 400byte max/ RxPDO 400 byte max, No of Unit numbers allocated 1, Current consumption (A) 5 V 0.34 : CJ1W-ECT21*