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Yealink T4 Series IP Phones User Guide V86.15

Yealink's user guide for the Yealink SIP-T48S, covering everyday calling, contacts, voicemail and phone settings (123 pages).
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About this user guide

About the T4 Series IP Phones User Guide V86.15

Yealink's user guide for the Yealink SIP-T48S, covering everyday calling, contacts, voicemail and phone settings (123 pages). This is version 86.15, last updated by Yealink on October 22, 2025, and you can read it right here or download it.

The SIP-T48S has been discontinued by Yealink, but it's still widely used, and this document is still the reference for setting it up. The Tech Team™ supports end-of-life Yealink phones and can help you plan a replacement when you're ready.

SIP-T48S is end of sale. Support options, dates and replacements

What’s inside

  1. Before You Begin
  2. Related Documentation
  3. Summary of Changes
  4. Changes for Release V86, Guide Version V86.15
  5. Getting Started
  6. Hardware Overview
  7. T48S/T48G Hardware
  8. T46S/T46G/T42S/T42G/T41S/T41P/T40P/T40G Hardware
  9. Power LED Indicator
  10. Line Key LED
  11. Screen and Icons
  12. Idle Screen
  13. Calls Screen
  14. Icons in the Status Bar
  15. Line Key Icons
  16. Entering Characters on T48S/T48G
  17. Using the Onscreen Keyboard
  18. Using the Phone Keypad and Dial Pad
  19. Entering Characters on T46S/T46G/T42S/T42G/T41S/T41P/T40P/T40G
  20. Call Features
  21. Changing the Default Account
  22. Placing Calls
  23. Placing a Call from the Dialer
  24. Placing Multiple Calls
  25. Placing a Call with a Speed Dial Key
  26. Placing a Call Back to the Last Incoming Number
  27. Redialing a Number
  28. Dialing a Hotline Number
  29. Placing an International Call
  30. Placing a Call from the Call History
  31. Placing a Call from the Directory
  32. Placing an Anonymous Call
  33. Placing Calls to Google Contacts
  34. Placing an Emergency Call from a Locked Phone
  35. Answering Calls
  36. Answering a Call
  37. Answering a Call When in a Call
  38. Answering a Call Automatically
  39. Switching Among the Handset, Speakerphone and Headset Modes
  40. Disabling Call Waiting

Phones covered

Yealink phones this user guide covers

Yealink SIP-T48S
SIP-T48SEnd of Sale

Versions

Other versions of this document

Related

More Yealink user guides

All user guides

FAQ

Questions about this document

Quick answers, and The Tech Team™ is a call away if you need more.

Contact us (800) 943-7675

Need help with your SIP-T48S?

The Tech Team™ can provision, update and troubleshoot your Yealink phones, and move your office onto smplVoice cloud voice.

Talk to a technician (800) 943-7675

Yealink and Yealink product names are trademarks of Yealink Network Technology Co., Ltd. Product information, images and documents are published by Yealink and provided here for reference by smplVoice. Firmware and documents are Yealink’s original, unmodified files.