A communication system comprising at least one communication unit. Each communication unit includes an interface port, a first-digital-subscriber-line port, a second-digital-subscriber-line port, and a central processing unit. The central processing unit is communicatively coupled to receive information indicative of the operability of the first-digital-subscriber-line port and the second-digital-subscriber-line port. The at least one communication unit is implemented on the physical layer in single-pair mode. The at least one communication unit is configured to switch from sending timeslots in dual-pair mode to sending timeslots in 1+1 protection mode when communication on one of the first-digital-subscriber-line port and the second-digital-subscriber-line port fails.