HandyTone 503 Analog Telephone Adapter

HandyTone 503 is the next generation of powerful,affordable, high quality and manageable IP telephony ATA/IAD for residential users and road-warriors. Its compact size, excellent voice quality, packed feature functionality and best-in-class price performance point enable consumers to maximize the power of IP voice and data connectivity. The HandyTone 503 is based on SIP standard and interoperable with most 3rd party SIP compliant devices and software. It featires 1 FXS telephone power, 1 FXO PSTN line port, dual 10M/100Mbps network ports, port status and message waiting LED, and a base stand for vertical positioning.

Same form factor as the new HT-502. Sturdier than the older 286/386/486/488/496 ATAs. Functionality comparable to the HT-496.


Call Handling Features

  • Caller ID display or block
  • Call waiting caller ID
  • Call waiting/flash
  • Call transfer
  • Hold
  • Call forward
  • Do not disturb
  • 3-way conferencing


  • 1 FXS telephone port (RJ11)
  • 1 FXO PSTN line port (RJ11) with lifeline support
  • Two (2) 10M/100 Mbps ports (RJ45) with integrated Nat router

Protocol Support

  • ICMP
  • DNS
  • DHCP
  • NTP
  • TFTP
  • PPPoE
  • STUN
  • TELNET protocols

LED Indicators

  • Power
  • WAN
  • LAN
  • LINE

RESET Button

  • Factory Reset Button

Device Management

  • Web interface or via secure (AES encrypted) central configuration file for mass deployment
  • Support device configuration via built-in IVR, Web browser or central configuration file
  • through TFTP, HTTP or HTTPS
  • Support Layer 2 (802.1Q, VLAN, 802.1p) and Layer 3 QoS (ToS, DiffServ, MPLS)
  • Auto/manual provisioning system
  • NAT-friendly remote software upgrade (via TFTP/HTTP/HTTPS) for deployed devices
  • including behind firewall/NAT
  • Syslog support

DHCP Server/Client

  • Yes

Audio Features

  • Advanced Digital Signal Processing (DSP)
  • Dynamic negotiation of codec and voice payload length
  • Support for G.723, G.729/E, G.711, G.726-40/32/24/16, iLBC, T.38 codecs
  • In-band and out-of-band DTMF (in audio, RFC2833, SIP INFO)
  • Silence Suppression, VAD (voice activity detection), CNG (comfort noise generation),
  • ANG (automatic gain control)
  • Adaptive jitter buffer control
  • Packet delay & loss concealment (PLC) & G.168 compliant Line Echo Cancellation
  • Support volume amplification
  • Support configurable Call Progress Tones

Network and Provisioning

  • Manual or dynamic host configuration protocol (DHCP) network setup; RTP and NAT
  • support traversal via STUN


Fax over IP

  • T.38 compliant Group 3 Fax Relay up to 14.4kpbs and auto-switch to G.711 for Fax
  • Pass-through (pending), Fax Data pump V.17, V.19, V.27ter, V.29 for T.38 fax relay


  • DIGEST authentication and encryption using MD5 and MD5-sess

LAN interface

  • 1xRJ45 10/100 Mbps Port

WAN interface 1xRJ45 10/100 Mbps Port

  • FXS telephone port
  • 1 x FXS (RJ11)

FXO telephone port (PSTN Port)

  • 1x PSTN pass-through and life line port

LED Power

  • WAN
  • LAN
  • LINE (green)

Universal Switching Power Adapter

  • Input: 100–240 VAC, 50-60 Hz
  • Output: 12VDC, 0.5A, UL certified


  • 25mm x 115mm x 75mm (when laying flat)
  • 115mm x 25mm x 75mm (standing up)


  • Approximately 0.6lbs (0.3kg)


  • Operational: 32° - 104°F or 5° – 45°C
  • Storage: 10°–130°F
  • Humidity 10% - 90% (non-condensing)

Ships With:

  • HT503 Main Case
  • Universal Power Adapter
  • Ethernet Cable
  • HT503 Vertical Stand

HT-503 configuration for Asterisk

Configuring HT-503 to work with asterisk can be difficult because some things are not well described into the GrandStream HT-503 User Guide.
For example, if you leave Wait for Dial-Tone Yes in the FXO configuration, but HT-503 does not recognize the TONE supplied by your CO, you're not able to make outgoing calls through PSTN.
A configuration template (with all parameters for HT-503, both FXS and FXO ports) which is usable with asterisk is provided inside the package
gsconf_x.y.tgz, named gsconf_503.txt.
Also, you can use the same gsconf package to automatically configure a set of 502/503 ATAs and PHONEs
through TFTP or HTTP. In this way is very very easy to configure a pool of HT-503 devices used to connect PSTN lines and/or analogue FAX/phones/cordless.

Grandstream HandyTone Comparison Guide

Where to buy

Created by: jrichard, Last modification: Tue 03 of Jun, 2014 (17:23 UTC) by sergei
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