Abstract: A procedure for replacing an existing switch (62) with a greater-capacity replacement switch (12) in a communication system (10) is disclosed. The replacement switch (12) has redundant interconnect memories (40) that can store different interconnect maps. The replacement switch (12) also has logic circuitry (48) that forces the replacement switch (12) to operate using only a selected one of the redundant interconnect memories (40). The procedure loads a transparent map into the interconnect memories. Next, the procedure couples the replacement switch (12) in series between drop facilities (14) and the existing switch (62) and between the existing switch (62) and line facilities (16). The coupling scheme and transparent map route communication through both the replacement switch (12) and the existing switch (62) without substantially affecting service.