Cisco VCO-IO-E1-4 is an E1 interface card for the Summa Four system, delivering four E1 spans for digital telecom connections. The card’s model name exactly matches VCO-IO-E1-4, and some product listings reference it as VCO4K 4-Span E1, confirming its four E1 channel capability. Designed to extend the Summa Four platform, this four-span E1 card enables multiple E1 lines to be interfaced within Cisco's Summa Four hardware ecosystem.
