Overview Product Description MMH904CA/56 - 4/8 -Port High Speed Multiplexer w/5600 kbps DSU/CSU (Refurbished) 90 Day Warranty Product Videos Custom Field Product Reviews Write a Review Write a Review × Multi-Tech MMH904CA/56 Rating * Select Rating 1 star (worst) 2 stars 3 stars (average) 4 stars 5 stars (best) Name Email * Review Subject * Comments *