An apparatus relates generally to serializer-deserializers. In such an apparatus, a first serializer-deserializer has a first data path and a data eye path. The first data path is coupled to a first data out interface of the first serializer-deserializer. A second serializer-deserializer has a second data path. The second data path is coupled to a second data out interface of the second serializer-deserializer. The data eye path of the first serializer-deserializer is coupled to the second data path of the second serializer-deserializer.