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Grandstream HT503 Robust Analogue Telephone Adapter

Robust analogue telephone adapter with 2 SIP accounts

Manufacturer Ref.: HT503 Product Ref.: GRAHT503UK
Grandstream HT503 Robust Analogue Telephone AdapterGrandstream HT503 Robust Analogue Telephone AdapterGrandstream HT503 Robust Analogue Telephone Adapter

Key features

  • Robust analogue telephone adapter
  • 2 SIP accounts
  • IP connectivity for telephones and fax machines
  • Built-in voice prompt menu

This product is no longer manufactured
Product end of life
This product have been replaced by Grandstream HT813 Adapter
+1 Year Extended Warranty
  • This product has a manufacturer warranty of
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  • Return costs are reimbursed by Onedirect, as well as shipping costs in case of replacement of defective products
Product information

Powerful and strong VoIP easy to manage

The Grandstream HT503 is a robust analog telephone adapter. This device offers the next generation powerful, affordable, high quality and manageable IP telephony.

Hop-on and Hop-off Call

The integration of a FXO and FXS port enables remote call origination and termination to and from the PSTN line, known as 'hop-on and hop-off' calling. This function coupled with its compact size makes it an ideal solution for road warriors seeking the savings and benefits of VoIP communication.

User-Friendly Voip

The Grandstream HT503 is designed to be a user friendly and affordable VoIP solution for both the residential user and the remote user. It has a built-in voice prompt menu for simple device configuration.


  • Up to 2 SIP accounts
  • Built-in voice prompt menu
  • 1 FXS telephone port (RJ11) & 1 FXO PSTN line port (RJ11) with power-outage life line support
  • Dual 10/100Mbps ethernet ports (RJ45) with integrated high performance NAT router
  • IP connectivity for telephones and fax machines
  • Advanced telephony features including caller ID, call waiting, 3-way conference calling with IP/PSTN, call transfer & message waiting indication.
  • Dimensions: 115 x 25 x 75mm
  • Factory reset button
  • LED indicators: Power, WAN, LAN, PHONE and LINE
  • Voice features: G711, G723, G729
Warranty 2 years
Dual WAN Without dual WAN
LAN ports 1
Dimensions 25 x 115 x 75 mm
In the box
Grandstream HT503
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