No longer works

March 2022 - the 3CX soft phone now only works with the 3CX PBX and is no longer a generic SIP client and so won't work with our SIP servers.

Legacy information

Older versions of 3CX was a software phone for Windows, iPhone and Android. See www.3cx.com/voip/softphone Be aware that this stand alone client 'does not receive any software updates or support' from 3CX.

The 3CX PBX is very different to this soft phone, and does work with our SIP service.

This SIP software on an iPhone just works.

3CX Feature Notes
Tested on FireBrick SIP Server	Yes - DOES NOT WORK ANY MORE
IPv6 Support	Possibly not
Versions Tested	iPhone
NAT Tested	Yes, Worked on 3G data services

Configuration

iPhone 3CX Configuration Settings Example
Name:	Your name
Display Name:	Your name, etc.
User:	Your phone number
ID:	Your phone number
Password:	******
Local PBX:	voiceless.aa.net.uk
External PBX IP:	voiceless.aa.net.uk
PBX Port:	5060
Stun:	Empty
Proxy:	Empty
Local SIP Port:	5065
First RTP port:	4000
TCP Transport:	Off
NAT HElper	Off
Echo CAncellation:	On
GSM	Off
G.711 (aLaw)	On
G.711 (uLaw)	Off

Notes

Disable STUN by deleting the stun server settings
Disable NAT helper
Enable/Disable echo cancellation depending on what works best for you
Force a-law audio (probably unnecessary).
Also works over 3G (dependant on signal!)
Also see Blog post

Firewall & Security

Also see the VoIP Security page for information about securing your VoIP service.