The MAX4818/MAX4819 high-bandwidth, low-on-resistance analog dual SPDT switches/4:1 multiplexers are designed to serve as integrated T1/E1 protection switches for 1+1 and N+1 line-card redundancy applications. Each MAX4818/MAX4819 replaces four electromechanical relays, significantly reducing board space, simplifying PC board routing, and reducing power consumption. These devices operate with 3.3V or 5V dual supplies for applications requiring T1/E1 signal switching in the line side of the interface transformer. Internal voltage multipliers drive the analog switches, yielding excellent linearity and low 4 typical on-resistance within the T1/E1 analog signal range. This high-bandwidth family of products is optimized for low return loss and matched pulse template performance in T1/E1 long-haul and short-haul applications. The MAX4818/MAX4819 are available in a tiny 16-pin, 5mm x 5mm, thin QFN package and are specified over the extended -40C to +85C temperature range.