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Cisco UC520 HowTo

NOTE The Cisco UC520 is obsolete hardware, went EOL March 2011 and end of sale date September 2011


NOTE All the text below was last edited in 2009, it is therefore likely out-of-date, inaccurate and in dire need of a refresh



The UC520 is a small-business integrated access device. This includes PBX, Key System, router, firewall and security functionality. It is Cisco's solution as an all-in-one device to support small to medium businesses and SOHO deployments. It uses Cisco Configuration Assistant for easy configuration of IP phone and trunking paramters, including operation with FreeSWITCH. Other Cisco and Linksys products can interoperate with the UC520 solution, including Voice over IP capable switches and wireless access points.

Basic Configuration

The UC520 uses common IOS concepts, and in fact runs IOS primarily. It also has some other
components bolted on top that provide the VoIP applications (voicemail, IVR, etc). Those other
components are in the "Unity Express" family, and more information can be found at
They run almost as a virtual machine on top of IOS, and have their own separate networking, SIP stack, etc.

They use concepts such as:

  • sip-ua: SIP peer (in our case, FreeSWITCH)
  • dial-peer: pattern-matching call routing logic
  • translation-rule: regexp-like search and replace call manipulation (ie. strip leading 9)
  • translation-profile: used to apply translation rules to calls

Calls from FS to UC520

  • Pre-CCA 1.9, you can just blindly dial any of the predefined 3 digit user extensions; you need to mess with translation rules to make the VM/IVR pilot numbers work.
  • After CCA 1.9, an ACL was added that you need to add your FS machine's IP to, or calls will not pass.. ACL is remarked as 'CCA_SIP_SOURCE_GROUP_ACL', and is commonly numbered 1 or 2.

Calls from UC520 to FS

First, setup a SIP UA entry (assumes your FS box is

authentication username uc500 password 7 encryptedgoo
retry invite 2
retry register 10
timers connect 100
registrar ipv4: expires 3600
sip-server ipv4:

Then you have to setup a dialplan ("dial-peer") entry, this one requires you dial '9' before your outbound number:

dial-peer voice 1900 voip
description FS SIP 7dig outbound
destination-pattern 9[2-9]......
session protocol sipv2
session target ipv4:
codec g711ulaw
no vad