REDCOM Sigma® Client is a SIP-based softphone app that provides secure voice, video, and chat with presence on Android™ phones and tablets.
Sigma Client is a stand-alone softphone app and not a VoIP service. To make calls, the app requires a standards-compliant SIP call control server or a subscription with a SIP-based VoIP service provider. REDCOM makes a great call controller called Sigma® Core, which we recommend to our Sigma Client users for the most optimal experience.
• Protect personal and corporate communications with Sigma’s 2048-bit RSA encryption
• Supports true dual registration to two or more independent SIP servers
• Wide range of standard and high definition audio codecs including G.711, G.722, G.729, Opus, and Speex
• Fully AS-SIP compliant
Unified Communications Features:
• Audio calls
• Video calls
• Full XMPP support, including:
o One-to-one chats
o Group administration
• Call forwarding
• Call transfer
• Call hold
• Call history (view & delete)
• Three-way calling
• Calling number delivery
• Missed call notifications
• TLS/SRTP for encrypted communications
• Call encryption (FIPS 140-2 validated)
• Support for ICE (XMPP)
• Noise suppression
• Echo cancellation (device dependent)
• Dial plan rules
• Auto start on bootup
• Mutual authentication
• Emergency call handling by native dialer
For more information on the Sigma Client features, please visit: http://www.redcom.com/sigma
When a user dials an emergency number from the Sigma Client app on a device with telephony support, the app is designed to pass the dialed digits to the mobile device's native cellular dialer, where the user can then attempt to complete the emergency call via their cellular carrier’s voice network. After handing off the dialed digits to the native dialer, the app is no longer involved in the call attempt. The emergency call, once placed, and any related location services are the responsibility of the cellular carrier. By default, the app treats ‘911’ as an emergency number and passes 911 calls to the native dialer.
The user can reconfigure the list of known emergency numbers within the app, which allows the user to control which dialed numbers, if any, are passed to the native dialer. Dialing emergency numbers from the app on a device without telephony support or reconfiguring the app to prevent emergency numbers from being passed to the native dialer will cause the app to process any emergency call as a VoIP call over the data network. Such calls can fail to complete due to any disruption of the app’s ability to communicate with its VoIP network service, such as power outages, lack of data network connectivity, etc. Placing a call through the VoIP network to report an emergency may also result in failure to direct the call to the correct emergency response center or failure to determine the user's correct location. For these reasons, REDCOM recommends that emergency calls be placed over the cellular carrier’s network using the device’s native dialer, if available. For devices without telephony support, REDCOM recommends that users always have an alternative means of accessing emergency operator services in case of disruption of VoIP service. REDCOM will not be liable for errors, delays, costs, damages, injury, or death resulting directly or indirectly from the use of the Sigma Client app for emergency calls.