Documented specifications
Yealink · Yealink lists the T73U in its current IP-phone catalogue and maintains current product and support records. Regional stock, exact order code, hardware revision, firmware support, accessory availability and provider approval remain separate evidence.
| Specification | Documented value |
|---|---|
| Display | 2.8-inch 320×240 color screen; readability, theme and viewing-angle acceptance remain deployment tests Source ↗ |
| Accounts and local keys | Up to 12 SIP accounts and eight LED line keys; account count, programmed identities, visible pages and concurrent calls are different quantities Source ↗ |
| DSS capacity | Up to 40 DSS assignments across five phone pages; Yealink separately states up to 234 programmable keys with as many as three cascaded EXP55 modules Source ↗ |
| Network and radios | Dual-port Gigabit Ethernet; Wi-Fi and Bluetooth are listed through optional WF50 and BT51 USB accessories rather than built-in T73U radios Source ↗ |
| Power and USB | IEEE 802.3af PoE class 2 or optional 5 V/2 A adapter; one USB 2.0 port supports listed accessory paths Source ↗ |
| Package | Phone, handset and cord, two-metre Ethernet cable, stand and quick-start guide are listed; power adapter and wall bracket are optional Source ↗ |
| Published audio controls | Yealink lists Acoustic Shield, Smart Noise Filtering and a 3 W speaker; performance and suitability remain exact-environment tests Source ↗ |
Unlisted fields remain unverified. Platform compatibility and remaining support life require confirmation for the exact ordered model.
Keep the T73U exact model distinct from adjacent T7X phones
Yealink's current catalogue places the T73U in the T7 Series alongside T73W, T74U, T74W and T77U. Similar names and shared design do not make those phones interchangeable. This record covers the wired T73U: do not transfer built-in Wi-Fi or Bluetooth claims from the T73W, T74W or another model.
Capture the label, order code, hardware revision, regional package and installed firmware before provisioning. A family page, reseller title or shared firmware family is not exact-device evidence.
Separate accounts, line keys, DSS pages and live calls
The datasheet lists up to 12 SIP accounts, eight LED line keys and up to 40 DSS assignments across five pages. These are different configuration capacities. Eight physical keys do not expose every identity at once, while 12 registered accounts do not prove 12 simultaneous calls, carrier channels or usable call starts.
Preserve the actual account set, page map, labels, active-call behavior and service capacity separately. Test line selection, hold, transfer, park, pickup, BLF, voicemail and failed-action recovery on the intended PBX instead of treating a programmed key as proof of server support.
Treat EXP55 modules and the shared USB path as one acceptance set
Yealink says the T73U can cascade up to three EXP55 color-screen modules and reach up to 234 programmable keys. The phone's USB interface can also serve a headset, storage, recording, EHS40 or optional radio accessory. Connector presence and the headline module count do not prove that every listed accessory can be attached, powered or operated together.
Inventory each module, cable, headset, adapter and recording device. Confirm the supported combination, power budget, boot order, key labels, page state, firmware prerequisites and recovery after restart or reprovisioning.
Commission Ethernet, optional radios and power independently
The T73U datasheet lists dual-port Gigabit Ethernet and supports Wi-Fi through WF50 and Bluetooth through BT51. Those optional USB accessories, approved headset combinations and regional radio rules remain procurement and compatibility evidence; they are not built-in radio results. Keep the phone and PC Ethernet paths, VLANs, LLDP, 802.1X, DNS, time and QoS visible.
Power is either IEEE 802.3af PoE class 2 or an optional 5 V/2 A adapter. Record the selected source and UPS boundary, then test cold boot, switch restart and accessory load. A link light, Wi-Fi association or Bluetooth pairing does not establish SIP registration or intelligible two-way media.
Bound audio and security claims to the installed path
Yealink publishes Acoustic Shield, Smart Noise Filtering, a 3 W speaker, TEE hardware encryption, secure boot, TLS 1.3, SRTP, certificate management, 802.1X and encrypted provisioning capabilities. These are manufacturer capabilities, not proof of intelligibility, protection, certificate validation or approved configuration on a particular deployment.
Preserve the provisioning owner, certificate chain, enabled services, management access, installed firmware and approved target. Inspect effective signaling and media negotiation on an authorized call, and evaluate acoustic behavior in the intended room rather than inferring either outcome from a menu label.
Confirm the regional package and physical deployment
The datasheet lists the phone, handset and cord, two-metre Ethernet cable, stand and quick-start guide as package contents, while the power adapter and wall bracket are optional. Treat the purchased regional order as authoritative. Verify desk angle or wall hardware, cable strain, display readability, handset switch behavior, hearing-aid workflow and accessibility requirements in the intended workspace.
A published operating range or accessory listing is not a suitability result. Keep environmental, ergonomic, acoustic and service acceptance evidence with the exact installed device.
Pilot provisioning, calls and recovery end to end
On an authorized service, test clean provisioning, registration, inbound and outbound calls, caller identity, mute, hold, resume, transfer, voicemail indication, BLF, pickup, conference, headset, speaker, restart, network loss, power loss and an approved firmware change. Repeat workflows that depend on an EXP55, USB accessory or optional radio path.
Preserve the assigned number, physical location and provider-approved emergency validation process without an uncoordinated live emergency call. No T73U, package, adapter, wall bracket, EXP55, USB accessory, radio dongle, network, PoE source, firmware, provisioning service, account, PBX, protected session, emergency workflow, availability, compatibility, price, audio result or live call was inspected or tested for this reference.
Sources & applicability
Primary references for the technical details above. Operational examples and planning checklists are VoIP.info editorial guidance.
- Yealink SIP-T73U product page ↗
- Yealink SIP-T73U datasheet ↗
- Yealink SIP-T73U support centre ↗
- Yealink current IP-phone catalogue ↗
Examples require adaptation to your topology. No live PBX or hardware testing is claimed.