BT120 Features and FUnctionality

Alexa built-in

Overview of BT120 Features 

Convenient Call Control via a built-in touch panel, an external tablet controller, the smartphone app, or a standard telephone

Multiple Voice Interfaces with hands-free speakerphone, and smartphone or POTS-based private voice mode 

Smartspeaker with a broad suite of Amazon AlexaTM Voice Service (AVS) features such as standard Alexa questions & commands, timers, alarms, reminders, and voice-enabled control of AVS-supported IoT devices

Set-Based Call Features such as Call hold, Call Transfer, and 3-way Calling

Superior Voice Quality with high-quality wideband codec (e.g., Opus, G.722, AMR WB) and network impairment handling (adaptive jitter buffer & NetEQTM, Packet Loss Concealment, etc.)

Flexible Network Deployment with Ethernet and WiFi for network redundancy, dual-homed mode for disjointed voice and data networks, VLAN tagging for traffic segregation, and VPN for enterprise network traversal  

VoIP Subscription Options. Enabling VoIP by either configuring the BT120 as an IP phone extension to an existing IPPBX or subscribing to an external VoIP service 

Secured Communications with HTTPS/HTTP2 secured connections for message exchanges, TLS for voice signaling, and SRTP with ZRTP/SDES key negotiation for secured media communication 

Digitmaps and Digit Replacement Rules delivering flexible numbering schemes to support diverse calling methods

Reliable Far-Field AVS Interactions and High-Quality Hands-Free Two-Way Audio with advanced audio processing and acoustic designs 

House Wiring Support. Equipped with intra-building lightning protection on its FXS port with support of up to 3 REN, the BT120 enables the use of house phones through the house wiring.

Convenient Call Control


Convenient Call Control using voice commands, a built-in touch panel, an external tablet controller, the smartphone app, or a standard telephone

Call Control through the BT120 Touch Panel

  • Call pickup/offhook
  • Phone mute (mute VoIP voice to remote party) 
  • Flash
  • Volume Control
  • Cloud Mute (mute voice to Alexa)

There are six buttons on the touch panel as shown in the diagram on the left. There are also LED displays associated with these buttons.  For details, please see BuddyTalk Device LED Definitions.

Note that in addition to the basic functions given in the diagram, some buttons are overloaded with other functions.  For example:

  • The device will announce its mater interface IP address when pressing the Flash button for 3 seconds.
  • Tapping the Flash button in the Private mode (the Flash button flashing green) will bring the device back to the Hands-Free mode. 
  • Depending on the call state and the device configuration settings, tapping the Flash button in the Hands-Free mode during an active call may have the device send out the Flash-Hook event to the VoIP server to trigger server-based call features. No signal will be sent to the Alexa server in this case.
  • The Alexa “Action” button can be triggered by pressing the Cloud Mute button for 3 seconds.

Call Control using the Mobile App

The BuddyTalk Mobile App offers the following call control mechanisms:

  • Calling using Mobile App dial pad
  • Call History based calling
  • Contacts based calling
  • Incoming call pickup or rejection
  • Phone Mute during action call

In addition to these call control mechanisms, the Mobile App also offers the Private mode voice interface as well as other device controls.  Please see BT120 Mobile App Features and Functionality

Note that when using Mobile App Contacts-based calling, the BT120 uses the Contacts in the Mobile App which may not be the same as the Contacts in the Alexa App used in the Voice Commands based calling.  Please also see Features and Functionality of BT120Tablet Controller and Mobile App for how the Contacts can be synchronized and imported.

Call Control using the Tablet Controller

The BuddyTalk Tablet Controller offers the following call control mechanisms:

  • Calling using the dial pad
  • Call History based calling
  • Contacts based calling
  • Incoming call pickup or rejection
  • Phone Mute during action call
  • Call hand-up on active call

In addition to these call control mechanisms, the Tablet Controller also offers other device controls.  Please see BT120 Tablet Controller Features and Functionality

Note that when using Tablet Controller Contacts-based calling, the BT120 uses the Contacts in the Tablet Controller which may not be the same as the Contacts in the Alexa App used in the Voice Commands based calling.  Please also see Features and Functionality of BT120Tablet Controller and Mobile App for how the Contacts can be synchronized and imported.

POTS-based Calling

The BT devices also offers the familiar RJ-11 POTS-based calling through the POTS phone connected to the device’s RJ11 port.  The user can also switch the call among FXS, BT120 Speakerphone, and the Mobile phone using the Mobile App. See Multiple Voice Interfaces below.

Multiple Voice Interfaces

 

The BT120 delivers Multiple Voice Interfaces with hands-free speakerphone, and smartphone or POTS-based private mode. 

Hands-Free Speakerphone Mode

Using advanced audio processing technologies and a hardware designed for far-field voice-initiated speech recognition, the BT120 offers high-quality hands-free speakerphone mode for convenient voice interface during a call. The high-quality speakerphone mode coupled with the Voice Commands based call control delivers true hands-free calling experience for the BT120 users.  

During an active call with the BT120 device in the Hands-free speakerphone mode, the BT120 Ring LED will flash green slowly, and the Phone LED on the device touch panel will display solid green.

Private Voice Mode through a Smartphone or a POTS Phone

The BT120  offers two private voice modes through user’s mobile phones and the POTS phones connected to the BT120 RJ-11 port.

The mobile phone based private voice mode is delivered through the Mobile App on the user’s mobile phone. Such a private voice mode can be activated by tapping the Private Mode icon on the Mobile App. During the mobile phone private voice mode, the user’s mobile phone mic and speaker becomes the audio input and output devices for the voice communication. Upon the user tapping the Private Mode icon on the Mobile App, the device announces “Private Mode On.” and the Flash LED on the BT120 touch panel will be blinking blue slowly.  During an active call, the BT120 Ring LED will display slow blinking green, and the Phone LED on the device touch panel will display solid green. 

Active call on Mobile App Private mode

The POTS-based private voice mode can be activated simply by picking up the POTS phone connected to the device’s RJ-11 port. During an active call, in addition to the Flash LED display (blinking blue slowly if the Mobile App Private mode is on), tthe BT120 Ring LED will display slow blinking green, and the Phone LED on the device touch panel will be solid green.

Active call on POTS phone, Mobile App Private Mode on

Active call on POTS phone, Mobile App Private Mode off

Switch the call among FXS, speakerphone, and the Mobile App Private mode.

  1. Switching from Speakerphone mode to POTS phone: When the call is conducted in the hands-free speakerphone mode, the user can switch it to the POTS phone simply by picking up the phone to conduct the phone conversation via the POTS phone. The Phone LED on the BT120 device will be solid green and the Ring LED will be flashing green slowly, indicating that the device is in an active call state.

Speakerphone Mode

Pick up POTS phone

POTS Mode

  1. Switching from POTS phone to Speakerphone mode: The user can switch the call back to the speakerphone mode by simply tapping the Phone button, and then hang up the POTS phone.  The Phone LED be solid green and the Ring LED will be flashing green slowly, indicating that the device is in an active call state.

POTS Mode

Tap Phone button

Speakerphone Mode

  1. Switching from Speakerphone mode to Mobile App Private mode: The user can switch the call to the Mobile App Private mode by tapping the Private Mode icon on the Mobile App.  The BT120 device will announce “Private Mode On.”, and the Flash LED will be blinking Blue entering the Mobile App Private mode. 

Speakerphone Mode

Tap Private Mode icon

Mobile App Private Mode 

  1. Switching from Mobile App Private mode back to Speakerphone mode: The user can switch the call back to the Speakerphone mode by tapping the green Private Mode icon on the Mobile App or tapping the Flash button (whose LED is blinking blue) on the BT120 Touch Panel. The BT120 device will announce “Private Mode Off” and the Flash LED goes off.

Mobile App Private Mode 

Tap Private Mode icon or Flash button

Speakerphone Mode

  1. Switching from Mobile App Private mode to POTS phone.  During an active call, the user can simply picks up the RJ-11 POTS phone to switch from the Mobile App Private mode to the POTS phone mode. The Flash LED will continue to be blinking blue, indicating that the BT120 was in the Mobile App Private mode, and when POTS phone mode ends, the device will return to the Mobile App Private mode.

Mobile App Private Mode 

Pick up POTS phone

POTS Mode

  1. Switching from POTS phone to Mobile App Private mode. To switch from the POTS phone mode to the Mobile App Private mode during an active call, the user will tap the Phone button if the device is already in the Mobile App Private mode (with the Touch Panel Flash LED blinking blue), or tap the Phone button on the Touch Panel followed by tapping the Mobile App Private Mode icon if the device was not in the Mobile App Private mode prior to the switch.

The device is already in the Mobile App Private mode

The device was not in the Mobile App Private mode prior to the switch

Device already in the Mobile App Private mode 

Device not in the Mobile App Private mode before switching

POTS w/ Mobile App in Private Mode

Tap Phone button

Mobile App Private Mode

POTS w/ Mobile App Not in Private Mode

Tap Phone button

Speakerphone Mode

Tap Private Mode icon

Mobile App Private Mode

Alexa Voice Service Qualified Smartspeaker

 

Utilizing advanced audio processing techniques, the BT120 is qualified by Amazon Alexa Voice Service as a far-field voice-initiated smartspeaker device supporting reliable 360o voice pickup for up to 9 feet away from the BT120 device. 

The BT120 supports a broad range of AVS smartspeaker features such as standard Alexa questions & commands, timers, alarms, reminders, and voice-enabled control of AVS-supported IoT devices.

Set-Based Call Features

 

Examples of the BT120 set-based call features are:

  1. Call hold: Put an active call on hold. 
  2. Blind call transfer: Put the call to be transferred on hold, dial the number to which the on-hold call is to be transferred, and transfer the call without waiting for the destination to pick up the call.
  3. Consulted call transfer: Put the call to be transferred on hold, dial the number to which the on-hold call is to be transferred, connect with the party to which the call is to be transferred, and then transfer the on-hold call.
  4. 3-way calling: The BT120 performs decoding of two remote voice streams, mixes the appropriate voice streams, encodes the resulting two out-going voice streams, and send two RTP streams to the two remote parties.

For BT120 feature call control using Tablet Controller and Mobile App, please see Controlling Feature Calls with BT120 Tablet Controller and Mobile App

Superior Voice Quality and Reliable VoIP Communication

 

The BT120 offers a set of voice codecs ranging from advanced Opus codec to simple G.711 codec for service providers or users to choose from based on the given network condition and bandwidth constraints for best VoIP calls. These codecs include both high-quality wideband codecs as well as simple narrow-band codecs: 

  • Narrow-band: G.711 (mu-law and A-law), G.729, iLBC, Narrowband Opus. 
  • Wideband: G.722, Wideband Opus, and AMR-WB (G.722.2).  

Additionally, the BT120 employs techniques such as adaptive jitter buffer, NetEQTM,, and packet concealment to minimize the voice quality degradation due to various network impairments such as network jitter, delay, and packet loss. 

In addition to voice processing, the BT120 supports in-band or RFC2833 for sending DTMF digits, and T.38 or G.711 fallback for reliable Fax transmission. 

Google MUSHRA Voice Quality Testing: 

  • NB Opus @11Kbps ≈ Uncoded 3.5KHz Low-pass filtered speech
  • WB Opus @20KHz ≈ Uncoded 7KHz Low-pass filtered speech  

Flexible Network Deployment

 

The BT120 may be deployed in a wide variety of office environments with different network configurations. To accommodate these varying network configurations, the BT120 offers the following network interfaces for easy deployment: 

  1. Redundant mode  
  2. Dual-Homed mode  
  3. VPN 
  4. VLAN tagging   

Note: 

  • VPN and VLAN are not available in the Dual-Homed mode.
  • VLAN tagging is application to the Ethernet interface only.
  1. Redundant mode.  When both Ethernet is connected and WiFi is enabled, the Ethernet is the active interface and the WiFi is the standby interface. The Redundant mode increases the connection reliability and can be used when voice and data services can be reached via the same network interface. This is the default mode and can be used in home and many office environments. Note: 
    • When the Ethernet interface loses connection, the WiFi becomes the active/main interface.  When the Ethernet interface recovers, the active/main interface returns back to the Ethernet interface. 
    • The Ethernet and WiFi interfaces can be configured to be in the same subnet for physical interface redundancy or in different subnets to increase network redundancy.  However, when the two interfaces are in different subnets, the Tablet Controller and the Mobile App’s network connections will have to be changed accordingly to be in the same subnet as BuddyTalk device in order for the Tablet Controller and the Mobile app to work with the BuddyTalk device. 
  1. Dual-Homed mode with both Ethernet and WiFi being active, connecting to two disjointed/separated networks. This configuration can be used when the voice network, where the internal IP-PBX and VoIP traffics reside, and the data network, through which the Alexa and BuddyTalk servers can be reached, are separate. Note:
    • The master interface through which the GUI console can be accessed when the device is configured in the Dual-Homed mode is the data network interface.  It is also the data network within which the optional Tablet Controller and the Mobile App communicate with the BT120 device. Therefore, in the initial setup before the Dual-Homed mode is configured, the user should have the BT120 device connect to the data network.
    • In the Dual-Homed mode, in addition to normal SIP signaling and RTP media, packets for VoIP server DNS queries and SIP registration are bound to the voice network. The Provisioning server network location is configurable. 
    • The VoIP proxy server and the BuddyTalk device can be in the same voice network subnet, as the case of the BuddyTalk device being an IP-phone extension to the enterprise IP-PBX, or in different subnets as some VoIP service providers have their VoIP network isolated from the Internet. See VoIP Enabling Options below.
  1. VPN for enterprise network traversal or for remote/work-from-home workers to connect to office IP-based phone systems. For enterprise network traversal, the built-in VPN client can be used when both voice and data services are reachable via the same network interface, but the enterprise firewall does not allow VoIP packets, signaling, media, or both, to go through. For remote/work-from-home workers, the VPN client can be connected to the office IP-based phone system via the office VPN server. Note:
    • The routing in the VPN mode can be set to have either only the VoIP packets go through the VPN tunnel or all traffic go through the VPN tunnel.
    • The BuddyTalk VPN client is based on the OpenVPN protocol. It can be connected to OpenVPN based VPN servers.
  2. VLAN tagging for voice data traffic segregation.  This is used in many office environments which use VLAN to segregate voice and data traffic and provide Quality of Service (QoS) for VoIP traffic. Note: There are two typical VLAN configurations as given below, and that the Tablet Controller and Mobile App will communicate with the BT device through the data subnet.
    • SIP signaling, voice media (RTP), and data traffic are separated into three different VLANs , with three different IP addresses belonging to three separate subnets. 
    • SIP signaling and voice media are configured with the same VLAN ID and IP address, which are different from the data VLAN ID and data IP address.   

Please see Configuring Network Interfaces for details. 

VoIP Subscription Options

 

The BT120 permits the configuration of a VoIP service provider, and utilizes the BuddyTalk SIP/VoIP stack for incoming and outgoing calls within the service provider’s coverage area. The BT120 may be configured as an IP phone extension to the office IP-PBX, or configured to subscribe to an external VoIP service. As an IP phone extension, the BT120’s Telephony Proxy Server setting will be configured with the enterprise IP-PBX IP address (may include its port number). When subscribing to an external VoIP service, the BT120’s Telephony Proxy Server setting will be configured with the VoIP service’s Proxy Server FQDN or IP address (may include its port number). In either case, an extension number or a PSTN number will be assigned to the BT120 device to allow both inbound and outbound calls. The configuration of such a SIP account can be done either through the BT120 device web console or through the BuddyTalk Setup App. 

Note that when configuring the BT120 device as an IP-Phone extension to an office IP-PBX, it is typical that some network configurations may be required to fit to the office networking requirements or constraints.  Additionally, Digitmaps and Digit Replacement Rules can be applied based on the IP-PBX dialing rule to offer users convenient and natural dialing in such an office environment.

SIP Telephony Account Configuration via BT120 Web Console  

SIP Telephony Account Configuration via Setup App  

Secured Communications

 
The BuddyTalk products have taken the various security steps to ensure security of the products, and have obtained the 3rd party security validation during the process of the AVS and ACM qualification.  The security ensuring mechanisms put in place include the following:. 
  1. Secured Connections: 
    • TLS1.2 with certificate validation
    • HTTPS connections to all external web servers
    • Certificate validation includes
      • SAN
      • Date/timestamp check for expiration
      • Certificate revocation check using OCSP
    • Secure websocket-based connections between the BuddyTalk device and the Tablet Controller, and between the BuddTalk device and the Mobile App 
  1. Over-the-Air (OTA) Provisioning 
    • HTTPS secured provisioning for configuration file and image download 
    • Encrypted configuration file
    • Encrypted and signed executable image
  1. VoIP Security 
    • TLS for signaling 
    • SRTP with ZRTP/SDES key management for media
  1. Device hardening with device-dependent password

Digitmaps and Digit Replacement Rules

 

Digitmaps are templates that are constructed based on the dialing plan to match different sequences of digits that users dial so that the device can send out the dialed digits to the respective SIP proxy/server in a timely manner. For the BuddyTalk product Digitmap rules and syntax, please see BuddyTalk Dialing Plan and Digitmaps.  Below is a Digitmap constructed for a typical U.S. dialing plan:

[2-9]xxxxxx|1[2-9]xxxxxxxxx|011x.T|[0-9*].#|*xx

When dialing from within an enterprise IP-PBX encvronment, it is typical that one or multiple prefix numbers are added to the callee numbers for external calls, and numbers with a smaller number of digits are used for internal extensions.  For example, a system reserves 4-digit numbers with the leading digit between 2 and 7 as internal extension numbers, the digit 9 is used as a prefix for external calls, and dialing 0 is to call the local operator/receptionist. The Digitmap for such a dialing plan is given below

0|[2-7]xxx|9[2-9]xxxxxx|91[2-9]xxxxxxxxx|9011x.T|[0-9*].#|*xx

The BuddyTalk products offer multiple convenient call control mechanisms, some are natural to dial with the prefix (e.g., POTS calling), and some are more natural not to have a prefix (e.g., voice commands based calling). To take into account these different dialing patterns, the above Digitmap can be augmented to handle dialings with or without prefix:

0.T|[2-7]xxx|9[2-9]xxxxxx|[2-9]xxxxxx.T|91[2-9]xxxxxxxxx|1[2-9]xxxxxxxxx|9011x.T|011x.T|+x.T|[0-9*].#|*xx

While the augmented Digitmap takes care of gathering and sending out the user dialed digits in a timely mannter, the dialed numbers may still be missing with the required prefixes, thus, insufficient for IP-PBXs.  This is where the Digit Replacement Rules can be used.  A properly constructed Digit Replacement scheme replaces or adds to the numbers matched by the Digitmap with the desired numbers or digits to fit the dialing plan requirements.  The Digit Replacement Rules for the dialing plan and the augmented Digitmap is given below:

 /|/|/|/9|/|/9|/|/9|+/9011|/|/

Please check Dialing Plans, Digitmaps, and Digit Replacement Rules for detail.  Please note that 

  • The Digit Replacement Rules are applied to the Voice Commands dialing, the TC dialing, and the Mobile App dialing, but not used in the POTS phone dialing.  Therefore, when using POTS phone to make calls, prefixes is required for external calls. 
  • The Digitmaps are applied to the POTS phone dialing in a digit-by-digit matching manner as the user dials the number, and the first (shortest) match will trigger the digits to be sent out.  On the other end, the Digitmap process chooses the longest match when used to choose the corresponding Digit Replacement rules to be applied to the Voice Commands dialing, the TC dialing, and the Mobile App dialing.
  • The Contacts used in the voice commands may not be identical to the Contacts used when calling through the Tablet Controller or the Mobile App, as the Contacts used in the voice command calling are from the Alexa App, while the Contacts used in the Tablet Controller and Mobile App calling are from the devices’ Contacts respectively.

BT100 with Various forms of dialing, some with and some without prefix

Reliable Far-Field AVS Interactions and High-Quality Hands-Free Two-Way Audio

 

The BT120 is Alexa Voice Service qualified in the category of far-field voice-initiated devices.  As such, a user can comfortably interact with the the Alexa Cloud through the B120 device to receive quality Voice Service Service in noisy environments and at distances in a natural manner.  Additionally, the BT120 is Alexa Communication certified, supporting 360o voice pick-up and high-quality hands-free two-way voice communication.    

Such reliable far-field voice-initiated Automatic Speech Recognition based interactions and high-quality hands-free two-way voice communication are accomplished through optimized hardware and mechanical design, advanced audio processing techniques, and a thoroughly tuned production and assembly process. 

Such reliable far-field voice-initiated Automatic Speech Recognition based interactions and high-quality hands-free two-way voice communication are accomplished through optimized hardware and mechanical design, advanced audio processing techniques, and a well tuned production and assembly process. 

  • Hardware and Mechanical Design. The BT120 device uses a 3-mic triangular array to allow 360o voice pick-up and the use of advanced processing techniques such as beamforming to increase the gain to the local talker’s speech while suppressing sound and speech from other directions. The BT120 also selects a speaker driver which has low total harmonic distortion with large dynamic range and full 48KHz bandwidth. Special attention has been paid in the mechanical design to maximum echo return loss and minimize distortions due to resonances. 
  • Advanced Audio Processing Algorithms. The BT120 employs advanced audio processing algorithms including Linear and Nonlinear Acoustic Echo Cancellation, Beamforming, Transient Noise Rejection, Advanced Noise Reduction, Dereverberation, Companding, and Parametric Equalization, delivering reliable far-field AVS interaction and high-quality hands-free 2-way voice communication.
  • ThoroughlyTuned Production and Assembly Process. Special attention has been paid to the BT120 production component qualification and assembly process to minimize component incurred nonlinearity and nonlinearity due to rub and buzz noise. Note that the performance of hands-free two-way voice communication is heavily dependent upon the amount of (frequency independent and highly frequency selective) nonlinearity present in the system.   

House Wiring Support

 

The BT120 is equipped with intra-building lightning protection on its FXS port.to allow phones from different rooms to be connected to the BT120 device through house wiring, therefore, extends use of calling with the BT120 device to a phone in another room in the home. 

The FXS port can support up to 2 ringer equivalence numbers (RENs) of load with a ring voltage configurable to be either balanced;60Vrms sinusoidal or balanced 67Vrms trapezoidal.

To assist in diagnosing issues with existing home wiring to allow a smoother installation process, the BT120 provides GR-909 line diagnostics for the following line tests:

 

Test Description
FEMF/HAZ

Detects any foreign line voltage present in house wiring

ROH Tests

Detects if any receiver is off-hook

REN Test
Detects current REN, and if it has exceeded limits
Resistive Faults Test
Detects any short between Tip and Ring in house wiring