Why the dual USB on the T42U?

So you can run a USB headset on one port and a Wi-Fi or Bluetooth dongle on the other. Single-USB models force you to pick one.

T42U vs T46U — should I upgrade for color?

The T46U is $30 more and adds a 4.3-inch color screen + 16 SIP lines. For desks where the screen matters, jump to the T46U. For utilitarian agents who don't look at the screen often, the T42U saves money.

Does the T42U support the EXP43 sidecar?

Yes — the T*U family is what added EXP43 support (the older T*G/S family is EXP40 only).

Will it auto-provision on voip.army?

Yes — standard Yealink RPS provisioning.

Yealink · T4 series · 12-line dual USB

Yealink T42UTwelve lines with two USB ports.

Twelve SIP accounts, a 2.7-inch backlit monochrome screen, dual gigabit ethernet with PoE, dual USB ports, EHS support. The T42U is the T42S with a second USB port — for desks that need to run a USB headset and a Wi-Fi or Bluetooth dongle at the same time.

Display

2.7″ backlit · 192×64 mono

SIP accounts

12 lines

Programmable keys

6 line + multi-page

Ethernet

Dual gigabit · PoE class 1

Audio

HD voice · dual USB · EHS · Opus

Power

PoE or 5V/1.2A adapter

$179 one-time

or rent for $11.99/mo — month-to-month, return anytime

Ships pre-configured · free next-business-day for orders $200+

Order a T42U Rent for $11.99/mo Datasheet (PDF) ↓

✓ Auto-provisioned out of the box ✓ Warranty replacement included with rental ✓ Free shipping on orders $200+

Yealink T42U voip desk phone — front view with handset and display — Yealink T42U

Why the T42U is on the catalog.

The T42U is the rarest T42 variant: 12 SIP lines plus dual USB plus EXP43 sidecar support. Yealink calls the T*U family their 'unified communications' tier — phones meant to bridge to softphone systems via USB while still functioning as standalone SIP endpoints. For agents who toggle between a hardware phone and a softphone, the dual USB lets you wire one for the headset and one for the host PC simultaneously.

Where this matters in practice: dispatch desks where the operator needs the phone AND the dispatch software's audio overlay piped through the same headset, contact-center agents running both Yealink and a CRM-integrated softphone in parallel, or any role where a USB connection to a PC is part of the standard workflow.

Where to skip it: typical office desks where only one USB device is used at a time. The T42S saves $10 and covers single-USB use cases identically. And if 12 SIP lines is genuinely excessive (most desks need 2-6), the T41U at $10 less gives you the same dual-USB capability with the standard 6-line cap.

Full technical specifications.

Display & user interface
Display	2.7-inch 192×64 backlit graphical LCD
Line keys	6 multi-page line keys
Soft keys	4 context-sensitive soft keys
VoIP & SIP
SIP accounts	Up to 12 SIP accounts
Protocols	SIP v2, TLS, SRTP, BLF/BLA
Codecs	Opus, G.722, G.711, G.729AB, G.726, iLBC
Provisioning	FTP/TFTP/HTTP/HTTPS, PnP, TR-069, RPS
Audio
HD voice	HD handset and HD speakerphone
Speaker	Full-duplex with AEC
Headset	RJ9 + 2 × USB + EHS
Connectivity
Ethernet	Dual 10/100/1000 Mbps gigabit
PoE	IEEE 802.3af Class 1
USB	2 × USB 2.0
Expansion	EXP43 sidecar (40 keys/module)
Power & physical
Power	PoE or 5V/1.2A adapter
Dimensions	Approximately 220 × 200 × 41 mm
Wall mount	Yes
In the box
Included	T42U handset, base, curl cord, ethernet cable, stand, provisioning card
Not included	Power adapter, USB devices, sidecar

How it works on voip.army.

Plug the T42U into PoE and ethernet. About a minute later it has registered to your extension. Same auto-provisioning flow as every other supported phone — no SIP credentials to type, no firmware to chase.

60s

Time from plug-in to first call

Boot, fetch config from our provisioning server, register, ready. About one minute on a normal connection.

SIP accounts on one phone

12 lines per phone. Each line key has a dual-color LED for status at a glance.

Programmable keys

6 line + multi-page mapped from the voip.army portal — BLF, paging, parking, transfer destinations.

Per-device onboarding fees

Bringing your own? Send us the MAC, factory-reset, plug in. No charge to add it to the fleet.

802.3af

PoE class

Standard PoE — any 802.3af-compliant switch from the last 15 years powers the phone without an adapter.

Yealink

Auto-provisioning template

Tested against every Yealink firmware release for T42U. We catch regressions before they reach your fleet.

Need T42Us for every desk?

Tell us how many you need and what extensions to map. We ship pre-configured next business day; you plug them in and they work.

Get a quote Start a free trial first

✓ Free shipping on orders $200+ ✓ 30-day hardware return ✓ Pre-configured before shipping

Yealink T42UTwelve lines with two USB ports.

Why the T42U is on the catalog.

Full technical specifications.

How it works on voip.army.

Time from plug-in to first call

SIP accounts on one phone

Programmable keys

Per-device onboarding fees

PoE class

Auto-provisioning template

Phones to compare it against.

Yealink T42S

Yealink T41U

Yealink T46U

Need T42Us for every desk?