Enhanced Call Management , Large storage for personal directory, callers log, and redial list, Tight Integration, Support for multiple IP telephony systems including BroadWorks®, Nortel, Sylantro, and Asterisk SIP, Remarkable Audio , Quality speakerphone with excellent voice delivery, Protect Your Investments, Firmware upgrades can be downloaded and installed in the field as standards develop and protocols evolve LEARN MORE: [PDF Document - Adobe Reader Required] Aastra Announces SIP Software Release 1.4 for Enterprise IP Telephones [PDF Document - Adobe Reader Required] Directions on Upgrading Firmware on Aastra Telecom IP Phone