An overview of the implemented standards is available here. Available features may vary depending on OS type and version.


  • Simple use, your parents are able to use it
  • Multiple SIP accounts
  • iCloud account syncing between multiple computers
  • Keychain support for encrypted password storage
  • Built-in SIP account sign-up at http://sip2sip.info
  • Handle TEL and SIP URLs clicked in other applications
  • Voice Over accessibility support

Contacts Management

  • Integrates System Address Book
  • Server Storage (XCAP protocol)
  • Directory search (LDAP protocol)
  • Bonjour neighbours (MDNS protocol)
  • Automatic backups

Audio Sessions

  • Wideband: Opus, G722 & AMR codecs
  • Narrowband: G711, GSM & AMR codecs
  • Answering machine
  • DTMF support
  • Silent mode
  • Call: recording, transfer, waiting
  • Mute microphone
  • Message Waiting Indicator (MWI)
  • ICE NAT traversal
  • Web page integration with caller information
  • Displays RTP end-point information
  • Displays codec, packet loss and RTT
  • Telephone dialpad
  • End-to-end aduio/video zRTP encryption
  • End-to-end chat OTR encryption

Multiparty Conferencing

Blink can conference audio calls locally. For more media types and advanced conferencing features, a conference server is required. Blink supports the following server side conferencing features:

  • Wideband Audio (using Opus codec)
  • Conference Information (conference-info event package)
  • Add/remove Participants (out-of-dialog REFER method)
  • Instant Messaging (MSRP chatroom support)
  • File Transfers (MSRP file transfer support)
  • Screen Sharing (JPEG streaming over MSRP)

Dialing Out

  • Support for SIP addresses and telephone numbers
  • Strip unwanted characters from telephone numbers
  • Replace leading + sign from phone numbers with a numeric prefix account
  • Custom prefix for outgoing calls to phone numbers
  • Automatic DTMF sending after connect with # as delimiter
  • Automatic account section for outgoing calls based on dial plans
  • Automatic fail-over to next next-hop when available
  • Redial for the last call

More Features

Accept/Reject Calls

  • Automatic accept calls
  • Displays the caller icon and name retrieved from Address Book
  • Rejects calls with 486 Busy (other devices keep ringing) or 603 Decline (all devices stop ringing)
  • Can accept partial offers when INVITE contains multiple streams
  • Speech recognition for alert panel commands
  • Speaks incoming caller name

Chat Sessions

  • Based on MSRP protocol with TLS and MSRP relay support
  • End-to-end encryption using OTR and SMP protocols
  • Privacy settings for local and remote storage of messages
  • Individual message delivery reports
  • Composing indication
  • Emoticons
  • Rich text support


  • H.264 codec
  • Resolutions: VGA and HD720p @30fps
  • ZRTP encryption


  • Based on SIP MESSAGE method
  • Emoticons

File Transfers

  • Based on MSRP protocol with TLS and MSRP relay support
  • Displays transfer speed and remaining time
  • NAT traversal using MSRP relay

Screen Sharing

  • MSRP protocol with TLS and MSRP relay support
  • VNC RFB protocol


  • SIP, DNS, RTP, MSRP and XCAP protocols trace to file or window


  • SIMPLE protocol (Presence Agent mode)
  • Policy Management (XCAP)
  • RLS Services
  • Offline status
  • User Icon

Missed Calls

  • History
  • One click Dial
  • Growl notifications