Important Official Statement First

Cisco never manufactured or released a model named SPA305within the entire Cisco SPA300 Small Business IP Phone series. The only official, released hardware variants of the SPA300 lineup are three confirmed models:

1. SPA301: Single-line basic IP phone (no LCD, single Ethernet port)
2. SPA302DKIT: DECT wireless handset kit with base station
3. SPA303: Three-line business IP phone (128×64 LCD, dual Ethernet pass-through ports, speakerphone, headset jack)

No Cisco datasheets, user guides, ordering catalogs, or support documentation contain any record of SPA305. The most likely scenario is that you misspelled or mislabeled SPA303 as SPA305. Below is the full official English product description of the Cisco SPA303 (the flagship desktop wired phone of the SPA300 series).

Cisco SPA303-G1 Full English Product Description

Listing Title

Cisco SPA303-G1 Small Business 3-Line SIP/SPCP VoIP Desk IP Phone, Entry Business-Class Multi-Line IP Telephone, 128×64 Backlit Monochrome LCD Display, Dual 10/100 Fast Ethernet Pass-Through Ports, Built-In Full-Duplex Wideband Speakerphone + 2.5mm Headset Jack, Universal 5V DC Power Adapter Included, Dual SIP v2 & Cisco SPCP Telephony Protocols, SRTP/TLS Secure Voice Encryption, TFTP/HTTP/HTTPS Auto Remote Provisioning, Complete Multi-Line Enterprise Calling Feature Set, End-of-Sale Legacy SMB VoIP Endpoint, Ideal for Small Business Office Staff, Retail Supervisors, Home Office Professionals and Light-Duty Administrative Users Requiring Multiple Concurrent Voice Lines

Full Commercial Overview

The Cisco SPA303 is the highest-spec wired desktop IP phone of Cisco’s Small Business SPA300 VoIP series, positioned above the single-line SPA301 model for small business employees handling multiple inbound and outbound calls daily. It delivers balanced cost-performance multi-line SIP voice communications with integrated PC Ethernet pass-through, wideband full-duplex speakerphone, graphical LCD navigation and dedicated headset support, without the premium price tag of the high-end SPA500 enterprise IP phone series.

This phone supports dual industry-standard telephony protocols: RFC 3261 compliant SIP v2 for compatibility with third-party hosted PBX, Asterisk, Broadsoft VoIP platforms; plus Cisco proprietary SPCP (Smart Phone Control Protocol) for seamless integration with Cisco UC500 Series unified communication gateways and SPA9000 voice systems. The entire SPA300 series reached End-of-Sale (EoS) on June 1, 2020, and End-of-Support (EoS) on May 31, 2025, classified as legacy discontinued VoIP hardware, succeeded by Cisco 7800/8800 enterprise IP phone lines and modern Webex Calling endpoints.

All device configuration management, dial plan editing, bulk unattended firmware upgrades and remote diagnostics are supported via secure auto-provisioning over TFTP, HTTP and HTTPS. An embedded web administration server provides full granular device configuration access, with separate administrator and standard user password permission tiers to prevent unauthorized system modification, enabling zero-touch mass deployment for multi-location small businesses and minimizing daily IT maintenance overheads.

Hardware, Display & Audio Architecture

1. Three Independent Dedicated Voice Lines

Three physical line keys with independent LED status indicators support simultaneous active calls, per-line call waiting, multi-line call hold and quick line swapping, tailored for administrative staff, retail managers and office supervisors managing multiple concurrent voice sessions.

2. Graphical LCD Display & Physical Control Layout

• Display Panel: 128 × 64 pixel backlit monochrome graphical LCD screen, supporting caller ID name/number display, real-time call duration timestamps, local call history logs, system menu navigation, network time/date and daylight savings time adjustment. Administrators can configure adjustable LCD contrast (1–30 levels) via the embedded web GUI.
• Hard Keys & Navigation Controls: Standard 12-key numeric dial pad; dedicated illuminated function hard keys for Mute, Headset, Speakerphone, Hold, Voicemail retrieval and system Setup menu; four-way directional navigation rocker with central select button for LCD menu browsing; universal volume control rocker to independently adjust handset, headset, speakerphone and ringtone audio levels.
• LED Status Indicators: Illuminated status LEDs on all dedicated function keys; standalone dedicated Message Waiting Indicator (MWI) LED to alert users of unread voicemail messages; built-in LED diagnostic test function for on-site hardware troubleshooting.

3. Complete Wideband Audio Subsystem

• Analog Wired Handset: High-quality ergonomic handset with native G.722 HD wideband audio support for natural, clear voice transmission and reception.
• Full-Duplex Hands-Free Speakerphone: Integrated front-panel speaker and dedicated microphone for hands-free conference calling with no audio cut-off during simultaneous talk/listen.
• Headset Interface: Standard 2.5mm TRS headset audio jack for compatibility with widely used office wired headsets.
• Supported Voice Codecs: G.711 A/µ law, G.726, G.729AB, G.722 HD wideband voice.
• Audio Optimization Technologies: Adaptive dynamic jitter buffer, voice frame loss concealment, Voice Activity Detection (VAD) silence suppression, Comfort Noise Generation (CNG), configurable audio packet frame sizes; DTMF transmission supported via in-band audio or RFC 2833 out-of-band SIP INFO signaling.

4. Chassis & Mounting Specifications

Compact matte black plastic desktop chassis with integrated foldable rear support stand for stable desk/countertop placement. Wall-mount bracket accessories are sold separately and not included in standard SPA303 factory packaging.

• Physical Dimensions: 220 mm × 198 mm × 30 mm (8.66 × 7.80 × 1.18 inches)
• Unit Weight: 0.68 kg (1.50 lbs)

Network, Power & Hardware Interfaces

1. Dual Switched 10/100BASE-TX Ethernet Ports

Two auto-sensing RJ45 LAN ports with integrated mini Ethernet switch, a core differentiator compared to the single-port SPA301:

• Primary WAN Port: Connects the IP phone to corporate LAN switches or VoIP gateways for SIP signaling and RTP voice media traffic.
• Secondary PC Pass-Through Port: Enables direct connection of desktop PCs, laptops or retail POS terminals to the office network through the phone, eliminating the need for extra wall Ethernet jacks and reducing cabling infrastructure costs for standard office workstation deployments.

Supported networking standards: Full IPv4 RFC compliance suite, DHCP client, DNS A/SRV resource records, ARP, ICMP, TCP/UDP, RTP/RTCP/RTCP-XR voice quality reporting, DiffServ QoS traffic marking, IEEE 802.1p / 802.1Q Layer 2 VLAN traffic prioritization, STUN NAT traversal for remote/home office NAT network environments, SNTP network time synchronization, CDP and LLDP network device discovery protocols.

2. Power Supply Specifications

A universal 100–240V AC switching power adapter (5V DC, 1.0A max output) is included as standard factory packaging content. The SPA303 does not support native IEEE 802.3af PoE operation; PoE functionality requires purchasing the separate Cisco POES5 power splitter accessory individually.

3. Additional Physical Interfaces

• RJ-9 modular wired handset connector
• 2.5mm TRS headset audio jack
• Recessed pinhole password-protected factory reset button (blocks unauthorized full configuration erasure)

Core Business Telephony Feature Set

All calling functions can be configured via the embedded web GUI or triggered through standard SIP star feature codes:

1. Multi-Line Call Handling: Per-line call waiting, call hold, music-on-hold, attended & blind call transfer, local three-way audio conferencing, call swap between active lines, automatic last number redial, on-hook dialing, global do-not-disturb (DND) silence mode.
2. Caller ID & Personalization: Caller ID name/number display, outbound caller ID blocking, anonymous call rejection, distinctive selective ringtones configurable per line/contact, support for up to 8 speed dial entries and a 100-entry local personal phone book stored persistently on the device.
3. Group & Utility Calling: One-touch intercom internal calling, group call pickup, call back on busy, system paging support.
4. Local Call Log Storage: Dedicated on-device storage for 60 entries each of dialed, received and missed calls, complete with timestamps and call duration data, viewable via the LCD screen or embedded web management portal.
5. Voicemail Integration: Native MWI voicemail notification via SIP SUBSCRIBE/NOTIFY messaging, dedicated one-touch voicemail retrieval hard key.

Security & Remote Management Capabilities

1. Encrypted Voice Communications: SRTP (Secure Real-time Transport Protocol) AES encryption for VoIP audio media streams, TLS encrypted SIP signaling traffic to block network eavesdropping and malicious signaling interception.
2. Multi-Tier Device Access Security: Dual-level password protection separating administrator full configuration rights and limited standard user access; HTTPS encrypted web management with factory pre-installed digital client certificates; MD5 HTTP Digest authentication for remote provisioning servers; password-locked factory reset function to prevent unauthorized full configuration wipe.
3. Automated Provisioning & System Monitoring: Secure unattended remote firmware upgrades without interrupting active voice calls, centralized syslog event logging, real-time call performance metric reporting, built-in network diagnostic tools for service providers and on-site IT administrators; configurable per-line event logging and RTCP-XR voice quality statistics reporting.

Environmental & Regulatory Specifications

• Regulatory Compliance Certifications: FCC Part 15 Class B electromagnetic compatibility, UL electrical safety certification, CE marking for European Union market compliance, A-Tick Australian telecommunications equipment compliance standard.
• Operating Environment: Indoor use only Operating Temperature: 0°C ~ +40°C (32°F ~ 113°F) Storage Temperature: -20°C ~ +70°C (-13°F ~ 185°F) Operating Humidity: 5% – 95% non-condensing Storage Humidity: 5% – 95% non-condensing
• Memory Architecture: Onboard flash memory for persistent firmware and configuration storage, dedicated SDRAM runtime memory for real-time multi-line call processing and embedded web server operation.
• Lifecycle Status: Discontinued End-of-Sale legacy small business VoIP hardware, fully replaced by modern enterprise IP telephony endpoints.
• Warranty: Standard Cisco limited hardware warranty for small business end users.

Key Specification Bullet Points

• Model Number: Cisco SPA303-G1
• Device Type: Small Business Three-Line SIP/SPCP VoIP Desk IP Phone
• Supported Telephony Protocols: SIP v2 (Full RFC 3261 Standard Suite), SPCP (Cisco Smart Phone Control Protocol for UC500 Series Gateways)
• Supported Voice Codecs: G.711 A/µ, G.726, G.729AB, G.722 HD Wideband Voice
• Display: 128 × 64 Backlit Monochrome Graphical LCD Screen
• Physical Buttons & Indicators: 12-key numeric dial pad, dedicated illuminated hard keys for Mute, Headset, Speakerphone, Hold, Voicemail, Menu; four-way navigation rocker; volume control rocker; multi-function LED status indicators + standalone MWI voicemail waiting LED
• Physical Audio Interfaces: RJ-9 handset port, 2.5mm headset jack, built-in full-duplex speakerphone
• Ethernet Interfaces: Dual auto-sensing 10/100BASE-TX RJ45 switched LAN ports (WAN uplink + PC pass-through secondary port)
• Power: Included universal 100–240V AC to 5V DC power adapter; no native PoE support (POES5 splitter sold separately)
• Mounting Method: Desktop foldable stand as standard; wall-mount hardware sold separately
• Supported QoS & Networking: DiffServ marking, 802.1p/802.1Q VLAN tagging, STUN NAT traversal, SNTP time sync, CDP/LLDP network discovery
• Security Features: TLS encrypted SIP signaling, SRTP AES encrypted voice media, dual-level admin/user password lock, HTTPS web management, password-protected factory reset
• Core Call Features: 3-line concurrent call support, call waiting, hold, attended/blind transfer, three-way conference, caller ID blocking, anonymous call rejection, intercom, group call pickup, speed dial, local call logs, DND silent mode, voicemail MWI notification
• Management Tools: Embedded web admin interface, TFTP/HTTP/HTTPS auto remote provisioning, syslog logging, remote unattended in-service firmware upgrades, RTCP-XR voice quality reporting
• Deployment Scenarios: Small business office staff desks, retail manager workstations, multi-line home office professionals, light-duty administrative staff requiring multiple concurrent voice lines
• Lifecycle Status: Discontinued End-of-Sale legacy VoIP phone
• Warranty: Cisco standard limited hardware warranty

Model Quick Reference

• The SPA303 is the 3-line upgraded variant of the single-line SPA301 within the SPA300 small business IP phone series, distinguished by three active voice lines, graphical LCD screen and dual Ethernet pass-through ports.
• Differentiators vs higher-tier SPA500 series: Limited to 3 voice lines, smaller monochrome LCD, no expansion module support, simplified feature set optimized for cost-sensitive small business deployments.
• Primary deployment advantage: Dual switched Ethernet ports eliminate redundant wall network jacks for combined PC + phone workstation setups, reducing cabling infrastructure costs for mass small business rollouts.
• Compatible with all standard SIP hosted PBX platforms and Cisco UC500 unified communications gateways via dual SIP/SPCP protocol support.