Cisco CP-3905 Unified SIP Phone — 1-Line VoIP | IEEE 802.3af PoE | Dual-Port 10/100 Ethernet | Speakerphone — New

The Cisco Unified SIP Phone 3905 (CP-3905) is a cost-effective, entry-level SIP VoIP desktop phone purpose-built for cubicles, classrooms, retail counters, manufacturing floors, hallways, and wall-mounted deployments. This single-line IP phone supports two concurrent calls per line and delivers clear voice communication via a full-duplex speakerphone with G.711a, G.711μ, G.729, G.729a, and G.729ab audio codec support. The graphical 128×32-pixel monochrome display provides scrollable two-line access to call features, services, and configuration, while fixed keys for redial, transfer, hold/resume, mute, and volume simplify everyday telephony. The built-in dual-port 10/100BASE-T Ethernet switch includes a LAN port and a downstream PC port, sharing a single wall drop to reduce cabling costs. Powered via IEEE 802.3af PoE (Class 1) or an optional regional power adapter (sold separately). Compatible with Cisco Unified Communications Manager 7.1(5) or later and Business Edition 3000, 5000, and 6000 platforms. The foldable foot stand supports both desktop and wall-mount use. Built with reground and recyclable plastics for an eco-responsible design.

Note: Power adapter is not included. PoE switch or injector required, or order an optional CP-3905-PWR regional adapter separately. Compatible with Cisco UCM platforms only — not supported on third-party call-control systems per Cisco official documentation.

Cisco CP-3905 Unified SIP Phone - Key Features & Benefits

• Single-Line SIP with 2 Concurrent Calls: Supports Session Initiation Protocol (SIP) on one line with up to two active calls simultaneously. Full call feature set includes call forward, call pickup, call waiting, call transfer, conference, group call pickup, redial, shared line, music on hold, Private-Line Automatic Ringdown (PLAR), Forced Authorization Codes (FAC), and message-waiting indicator
• IEEE 802.3af PoE (Class 1) — Single-Cable Installation: Powered via IEEE 802.3af Power over Ethernet Class 1 over a single Ethernet cable — no separate power adapter required when connected to a PoE-capable switch or injector. Optional regional power adapter (CP-3905-PWR-NA= for North America; regional variants available) sold separately for non-PoE environments. Power input: 1.5A at 4.2V DC
• Dual-Port 10/100 Ethernet — LAN + PC Passthrough: Built-in 10/100BASE-T two-port Ethernet switch with one RJ-45 LAN port and one downstream PC access port — share a single wall drop between the phone and a desktop PC to reduce cabling infrastructure costs. Supports DHCP or static IP, TFTP firmware upgrades, DNS, RTCP monitoring, Syslog, and embedded web server for configuration and statistics
• 128×32 Graphical Display & Full Button Layout: 128×32-pixel monochrome graphical display provides a scrollable two-line view for call status, directories, and settings. Button set includes: Select, Back, two-way navigation, Redial, Transfer, Hold/Resume, Mute, Volume Up/Down, Speakerphone, and standard dial pad. Supports 30+ localized display languages including English, Spanish, French, German, Chinese, Japanese, Korean, Russian, Arabic, and more
• Wall-Mountable & Eco-Friendly Design: Foldable single-position foot stand supports both desktop and direct wall-mount deployment (mounting holes on phone base). Constructed with reground and recyclable plastics. Memory: 4 MB flash / 32 MB SDRAM. Dimensions: 8.07 × 5.91 × 2.11 in. Weight: 1.31 lbs (20.96 oz). Certifications: FCC Part 15 Class B, CE, UL 60950, CAN/CSA-C22.2 No. 60950

Cisco CP-3905 Unified SIP Phone - Technical Specifications

• Manufacturer: Cisco
• Part Number: CP-3905=
• Product Type: Unified SIP Desktop IP Phone
• Protocol: SIP (Session Initiation Protocol)
• Lines / Calls: 1 line • Up to 2 concurrent calls
• Display: 128×32-pixel monochrome graphical LCD
• Speakerphone: Full-duplex
• Audio Codecs: G.711a • G.711μ • G.729 • G.729a • G.729ab
• Voice Quality: Comfort-Noise Generation (CNG) • Voice-Activity-Detection (VAD)
• Ethernet: Dual-port 10/100BASE-T (1× LAN RJ-45 + 1× PC access RJ-45)
• Power: IEEE 802.3af PoE Class 1 • Optional local adapter (sold separately) • Input: 1.5A / 4.2V DC
• Memory: 4 MB flash • 32 MB SDRAM
• Handset Jack: RJ-9 (4-conductor)
• Physical Dimensions: 8.07 × 5.91 × 2.11 in. / 205 × 150 × 53.5 mm (slab mode, stand folded)
• Weight: 20.96 oz / 594.3g (1.31 lbs)
• Operating Temperature: 32–104°F (0–40°C)
• Storage Temperature: 14–140°F (−10–60°C)
• Relative Humidity: 10–95% non-condensing
• Call Manager Compatibility: Cisco UCM 7.1(5)+ • BE3000 v8.6 • BE5000 v8.5+ • BE6000 v8.5+
• Call Features: Call forward • Call pickup • Call waiting • Call transfer • Conference • Group call pickup • Redial • Shared line • Hold/Resume • Music on hold • Message-waiting indicator • PLAR • FAC • Auto barge
• Provisioning: DHCP / Static IP • TFTP firmware upgrades • DNS • Web configuration server • RTCP • Syslog
• Display Languages: 30+ including English, Spanish, French, German, Chinese, Japanese, Korean, Russian, Arabic
• Certifications: FCC Part 15 Class B • ICES-003 Class B • CE (2004/108/EC, 2006/95/EC) • UL 60950 • CAN/CSA-C22.2 No. 60950 • EN 60950 • IEC 60950 • VCCI Class B
• Design: Reground and recyclable plastics • Foldable foot stand • Wall-mountable
• Color: Charcoal
• Condition: New

Cisco CP-3905 Unified SIP Phone - Frequently Asked Questions (FAQ)

• Is the power adapter included?
  No — the CP-3905 does not include a power adapter. It is powered via IEEE 802.3af PoE (Class 1) from a PoE-capable switch or injector. If you need a power adapter, order an optional regional adapter separately (e.g., CP-3905-PWR-NA= for North America).
• What call manager does this phone require?
  The CP-3905 is compatible with Cisco Unified Communications Manager (UCM) 7.1(5) or later, Cisco UCM Business Edition 3000 v8.6, Business Edition 5000 v8.5+, and Business Edition 6000 v8.5+. Per Cisco official documentation, this phone is not supported on third-party call-control systems.
• Does this phone support Gigabit Ethernet?
  No — the CP-3905 uses 10/100BASE-T Fast Ethernet (dual-port). It does not support Gigabit speeds. Both the LAN port and the downstream PC passthrough port operate at up to 100 Mbps.
• Can this phone be wall-mounted?
  Yes — the foot stand folds flat and the phone base includes mounting holes for direct wall installation. No separate wall-mount kit is required.
• What is the difference between CP-3905 and CP-3905=?
  CP-3905= is Cisco's spare/standalone unit ordering number (standard retail box with handset and handset cord). Both are the same physical phone — the = suffix denotes a spare-unit or field-replaceable SKU in Cisco's ordering system.

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