Introduction
Cisco 805 is a model within Cisco Systems’ 800 series of Integrated Voice Gateways, released in the mid‑2000s. The device was engineered to provide voice, data, and video services to small and medium‑sized branch offices, offering a cost‑effective solution for organizations seeking unified communications without the need for a full‑scale enterprise system. The Cisco 805 combined multiple interfaces, voice processing capabilities, and a streamlined operating system to support voice over IP (VoIP) and legacy Time‑Division Multiplexing (TDM) telephony.
The platform was designed with a focus on ease of deployment, flexible connectivity, and integration with Cisco Unified Communications Manager (CUCM). It supported both SIP and H.323 protocols, enabling compatibility with a range of VoIP endpoints. Cisco 805 also featured built‑in support for Cisco TelePresence, allowing high‑definition video conferencing within the same device.
History and Development
Development Context
During the early 2000s, the telecommunications industry was undergoing rapid transformation, with IP‑based voice systems becoming increasingly prevalent. Cisco Systems, already a leader in routing and switching technology, sought to expand its unified communications portfolio by developing small‑to‑medium office solutions that could bridge legacy TDM networks with modern VoIP infrastructure. The 800 series, launched in 2002, was the result of this initiative.
Within the 800 series, Cisco identified a need for an integrated voice gateway that could handle a moderate number of voice channels while providing robust data connectivity. The 805 was conceived to fill the gap between the compact 802 and 804 models and the larger 806/807 models, offering 24 TDM voice channels, a higher port count, and additional performance enhancements.
Release Timeline
The Cisco 805 was first announced in the spring of 2005. The initial release came with a 12‑channel TDM interface, two 10/100 Ethernet ports, and support for up to 20 concurrent SIP endpoints. A subsequent firmware update in late 2005 expanded the device to support 24 TDM channels and added a 1 GbE port. The final production model, released in early 2006, incorporated 24 TDM ports, a 1 GbE port, and additional security features such as IPsec VPN support.
Throughout its lifecycle, Cisco issued several incremental firmware releases, each adding new capabilities such as enhanced call routing, improved QoS, and support for newer SIP codecs. By 2008, the device had become a popular choice for many small enterprises, particularly those that required a cost‑effective solution to integrate legacy PBX systems with VoIP.
Discontinuation and Legacy
Cisco began phasing out the 800 series in favor of newer platforms in the early 2010s, following the advent of the 3000 and 4000 series Integrated Voice Gateways. The 805 was officially discontinued in 2011, with Cisco offering a 5‑year support window for existing customers. Despite the end of mainstream production, many organizations continued to deploy Cisco 805 devices due to their robust hardware and compatibility with existing Cisco infrastructure.
Technical Specifications
Hardware Architecture
The Cisco 805 is built around a dual‑core processor architecture, featuring a 400 MHz CPU and a dedicated voice processing engine. The device incorporates 512 MB of DDR RAM and 2 GB of non‑volatile flash storage for firmware and configuration data. Power is supplied via an external adapter rated at 24 VDC, 2 A.
Hardware modules include a combination of integrated 24‑channel TDM ports, a 10/100 Ethernet port, and a 1 GbE Ethernet port. The TDM ports support both digital (DS1/E1) and analog interfaces, enabling a wide range of telephone connections. The Ethernet ports provide high‑bandwidth connectivity for VoIP, data, and video traffic.
Connectivity and Interfaces
- 24 × TDM ports (DS1/E1) – capable of handling up to 24 simultaneous voice channels.
- 2 × 10/100 Mbps Ethernet ports – for data connectivity and basic VoIP routing.
- 1 × 1 GbE Ethernet port – optional high‑bandwidth link for video and data.
- USB 2.0 port – for firmware updates and peripheral connectivity.
- Power jack – 24 VDC input.
The device supports a variety of line cards and transceivers, allowing network administrators to tailor the interface mix to their specific needs. Each TDM port can be configured for either full‑rate or reduced‑rate operation, depending on the required voice channel density.
Processing and Performance
The 400 MHz dual‑core CPU is optimized for packet processing and VoIP call handling. In typical configurations, the device can handle up to 200 concurrent SIP calls while maintaining low packet loss and minimal latency. The integrated voice engine processes codec conversion, echo cancellation, and bandwidth management, ensuring high call quality even under heavy load.
Quality of Service (QoS) features are implemented at the hardware level, enabling priority tagging for voice, video, and data packets. The device supports standard QoS mechanisms such as DiffServ, MPLS traffic engineering, and traffic shaping, allowing administrators to allocate bandwidth appropriately across applications.
Software and Operating System
Cisco 805 runs on the Cisco Integrated Services Router (ISR) operating system, version 12.4 and later. The software stack includes modules for SIP, H.323, ISDN, TDM, and MPLS. The operating system offers a command‑line interface (CLI) and a web‑based management console, providing flexibility in configuration and monitoring.
Firmware updates are distributed in the form of software images that include bug fixes, security patches, and new feature support. The device uses a bootloader that verifies the integrity of the image before loading, ensuring reliable operation. Cisco also provides a secure over‑the‑air (OTA) update mechanism for remote management of large deployments.
Functional Capabilities
Voice Services
The Cisco 805 supports both traditional TDM voice routing and VoIP protocols. With its 24 TDM ports, the device can interconnect with legacy PBX systems, providing digital trunking and line management. The voice engine processes common codecs such as G.711, G.729, and G.723.1, offering low‑delay, high‑quality call handling.
VoIP capabilities include SIP and H.323 registration, proxying, and media handling. The device can function as a SIP proxy or registrar, enabling transparent routing of VoIP traffic to CUCM. SIP trunking is supported with the ability to configure multiple trunks, QoS policies, and NAT traversal settings.
Data Services
Beyond voice, the Cisco 805 provides data routing functions typical of a small‑to‑medium office router. It supports static routing, dynamic routing protocols such as OSPF and EIGRP, and policy‑based routing. IPsec VPN support allows secure site‑to‑site connections, facilitating remote branch connectivity.
The device also implements Layer 2 features including VLAN tagging, port security, and spanning‑tree protocol (STP). These features enable integration into larger enterprise networks, allowing the 805 to coexist with other Cisco routers and switches.
Security Features
Security is addressed through multiple layers. The device supports IPsec VPN for encrypted traffic, with support for IKEv1 and IKEv2. User authentication is handled through RADIUS or TACACS+ integration, ensuring that only authorized administrators can access configuration interfaces.
Network security also includes ACLs (access control lists) for packet filtering, DHCP snooping, and dynamic ARP inspection. The device supports secure shell (SSH) and HTTPS for management, and provides a secure HTTP configuration interface for web management. Firmware integrity checks prevent unauthorized updates.
Management and Monitoring
The Cisco 805 offers extensive monitoring capabilities. Built‑in SNMP support allows integration with network management systems. The device exposes various MIBs for real‑time performance metrics such as CPU usage, memory utilization, packet statistics, and call detail records (CDRs).
CLI commands provide granular control over configuration, troubleshooting, and diagnostic functions. Log files are stored in persistent memory, offering insight into system events, call quality metrics, and error conditions. The web console offers a simplified interface for routine configuration tasks, though advanced users prefer the CLI for precision.
Deployment Scenarios
Small and Medium Office Environments
One of the primary target markets for the Cisco 805 is small and medium offices requiring a unified communications solution. In these settings, the device consolidates voice, data, and video traffic onto a single platform, reducing hardware footprints and simplifying cabling.
Typical deployments involve connecting the 805 to a primary Cisco router via the 1 GbE port, with local Ethernet switches attached to the 10/100 ports. The TDM ports are connected to existing analog or digital PBX lines, allowing gradual migration to VoIP. The device’s integrated SIP services provide a cost‑effective gateway for business‑grade phone systems.
Branch Office Connectivity
Branch offices often lack dedicated voice infrastructure. The Cisco 805 can serve as a voice gateway, routing calls to the corporate CUCM over IP. With support for IPsec VPN, the device establishes secure tunnels to the headquarters, enabling reliable telephony even over public internet links.
In this scenario, the 805 can also provide basic data routing, eliminating the need for a separate WAN router. By configuring route maps and access lists, administrators can segment traffic, prioritize voice, and manage bandwidth allocation.
Integration with Cisco TelePresence and VoIP
The device’s support for high‑definition video makes it suitable for small video‑conferencing setups. When paired with Cisco TelePresence endpoints, the 805 can route video streams, manage codec negotiation, and apply QoS to maintain call quality.
For VoIP deployments, the Cisco 805 can act as a SIP proxy or registrar, integrating seamlessly with CUCM or third‑party SIP servers. This allows organizations to deploy VoIP on a limited budget while retaining compatibility with legacy infrastructure.
Compatibility and Interoperability
Integration with Cisco Unified Communications Manager
Integration with CUCM is a key feature of the Cisco 805. The device registers with CUCM over SIP, receives provisioning information, and uses it to configure trunks, routing tables, and QoS policies. CUCM’s CallManager service provides the 805 with real‑time information about active calls and resource allocation.
CUCM also offers a RESTful API that can be used to programmatically configure the 805, enabling automated provisioning and scaling. This integration eliminates manual configuration of each device in large deployments.
Support for Legacy TDM Systems
The 805’s 24 TDM ports can interface with analog, DS1/E1, or ISDN trunks, allowing a mix of digital and analog lines. The device includes an ISDN BRI (Basic Rate Interface) module, providing an additional 4 analog ports for PSTN connectivity.
Echo cancellation and jitter buffer management within the voice engine ensure that calls between TDM and VoIP remain clear. The device also supports DTMF via RFC 4733, facilitating compatibility with most PBX systems.
Third‑Party VoIP Servers and Endpoints
While Cisco 805 devices integrate best with CUCM, they also support third‑party SIP servers. Through configuration of proxy settings, registration URIs, and authentication credentials, the device can interoperate with a wide range of VoIP solutions.
Similarly, the device can connect to H.323 servers for video or conferencing. By configuring media profiles and bandwidth allocation, administrators can ensure that both Cisco and non‑Cisco endpoints maintain acceptable call quality.
Maintenance and Support
Firmware Updates
Cisco distributes firmware images through its support portal, requiring customers to log in and download the appropriate image for their hardware version. Firmware updates are performed via the CLI using the “upgrade” command or via the web console’s upload function.
After a firmware upgrade, the device performs a verification step before reloading. If the verification fails, the device reverts to the last known good image, ensuring minimal disruption.
Hardware Diagnostics
The 805 includes a suite of diagnostic commands that enable administrators to test individual ports, measure packet loss, and identify hardware faults. Commands such as “show interface”, “show tdm”, and “debug tdm” provide real‑time status and error reports.
When a port fails, the device logs a detailed error message, including line code, error count, and time stamp. This facilitates rapid troubleshooting and replacement of faulty modules.
Disaster Recovery and Redundancy
Disaster recovery is handled through a combination of redundant firmware images and hardware backup. The device can load an alternative image from the backup partition if the primary firmware becomes corrupted. Administrators can also configure a hot standby pair of 805 devices, using VRRP (Virtual Router Redundancy Protocol) for failover.
In addition, Cisco’s TFTP and NTP servers provide a mechanism for network‑wide configuration backups and time synchronization. The device’s NTP configuration ensures that CDR timestamps remain accurate across the organization.
Common Issues and Troubleshooting
Call Quality Degradation
Possible causes include insufficient bandwidth, incorrect QoS configuration, or congestion on the TDM ports. Administrators should verify that the DiffServ marking on voice packets matches the corporate QoS policy and that no VLAN tags are causing packet drops.
Tools such as “voice interface” and “monitor cdr” provide metrics on packet loss and jitter. Adjusting codec settings or shifting traffic to the 1 GbE port can alleviate congestion.
Registration Failures with CUCM
When the 805 fails to register with CUCM, check the network connectivity between the device and CUCM. Verify that the SIP port is open on the firewall, that the device’s IP address is reachable, and that NAT settings are correct.
In cases of NAT, the device’s “sip nat” command can be used to configure traversal. Enabling “sip registrar” and setting the proper “sip registrar-id” often resolves registration issues.
Hardware Port Faults
Physical port errors can be identified through the CLI command “show interface tdm”. Errors such as “loss of sync” or “frame error” indicate hardware faults. The device logs these errors in the syslog. Replacing the affected module typically resolves the issue.
For TDM port failures, it is recommended to replace the entire line card if multiple ports are affected, as the fault may be related to the board’s hardware.
Best Practices
- Prioritize voice traffic with DiffServ markings and configure appropriate traffic shaping.
- Use VPN tunnels for secure trunking to CUCM, ensuring call confidentiality.
- Implement ACLs to restrict access to management interfaces, and use RADIUS/TACACS+ for authentication.
- Regularly update firmware to patch security vulnerabilities and improve performance.
- Use SNMP and CDR logging for proactive monitoring and billing integration.
Conclusion
The Cisco 805, though no longer in mainstream production, remains a valuable platform for many small to medium enterprises. Its combination of TDM and VoIP support, robust QoS, and integration with Cisco’s Unified Communications ecosystem make it a versatile choice for unified communications deployments. While newer devices offer enhanced features and higher scalability, the 805’s proven hardware reliability ensures that it can continue to serve as a dependable voice gateway for years to come.
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