NEC Miniature Signal Relay UB2 Series NEC's Miniature Signal Relay UB2 Series are super-compact, SMD typ, slim-packaged relays for dense mounting featuring Telcordia (2500V) and FCC (1500V) surge capacity. NEC's Miniature Signal Relay UB2 Series consumes low power (100-140mW) and is ideal for electronic switching systems, PBX, terminal equipment, and telephone systems.