A router with built-in hardware for connecting directly to Integrated Services Digital Network (ISDN) lines.
ISDN routers - also called ISDN access routers because they provide direct connectivity to a wide area network (WAN) connection - are a popular way of providing SOHOs (Small Office/Home Offices) with 128-Kbps dial-up ISDN connectivity to the Internet or to a remote private corporate network through the industry-standard Point-to-Point Protocol (PPP).
They typically support up to 10 users in a small workgroup Ethernet local area network (LAN) and might provide some firewall, network address translation (NAT), or Dynamic Host Configuration Protocol (DHCP) support.
ISDN routers include RJ-11 jacks for connecting several analog phones, fax machines, or other devices for simultaneous voice/fax/data connectivity. Built-in data compression can increase the effective bandwidth by a factor of 5 or higher.
Some ISDN routers include built-in hubs for quick connectivity. Many are manageable using a remote Telnet connection or through Simple Network Management Protocol (SNMP).