The Cisco^® IP Phone 7800 Series is a cost-effective, high-fidelity voice communications portfolio designed to improve your organization’s people-centric communications, while reducing your operating costs.

It combines an attractive new ergonomic design with “always-on” reliability and secure encrypted communications. The Cisco^® IP Phone 7800 Series delivers advanced IP Telephony features and crystal clear wideband audio performance to deliver an easy-to-use, full-featured voice communications experience on Cisco on-premises and hosted infrastructure platforms and third party hosted call control.

The Cisco^® IP Phone 7800 Series introduces four models to the Cisco IP Phone portfolio. From left-to-right (Figure 1), they are:

●   Cisco IP Phone 7811 supporting one line (available in charcoal only)

●   Cisco IP Phone 7821 supporting two lines (available in charcoal and white)

●   Cisco IP Phone 7841 supporting four lines (available in charcoal and white)

●   Cisco IP Phone 7861 supporting sixteen lines (available in charcoal and white)

https://www.cisco.com/c/en/us/products/collateral/collaboration-endpoints/unified-ip-phone-7800-series/data-sheet-c78-729488.html