communications apparatus , including client interface units coupled to network service lines for sending and receiving data carried by the service lines in accordance with respective communication protocols . the cius include at least first and second cius that communicate with respective first and second channels of the data operating in accordance with different , respective first and second protocols . the apparatus includes optical interface units , coupled to a passive optical network and modulating optical radiation responsive to the data so as to convey the data over the pon . the apparatus further includes a connectivity unit which conveys the data between the cius and the oius , while mapping the channels to the oius so that data from the first and second channels is carried in alternation by one of the oius to first and second users of the pon communicating respectively according to the first and second protocols .