DECT VoIP Combination Delivers Dependable Enterprise Wireless Voice

By Brad (Biju) Oommen

Originally published in UC Network Management

April 22, 2019

By Biju Oommen -

A Digitally Enhanced Cordless Telephony (DECT) VoIP base station paired with DECT handsets provide a secure and dependable wireless communication solution. To the user community in any industry, the DECT air interface/DECT radio technology via dedicated and reserved radio frequency bands are less likely to suffer from radio frequency (RF) interference. They provide mobility, high voice quality and security for enterprise telephony applications. DECT VoIP based technology opens many new avenues to support flexible and simple enterprise business voice applications. From an end user perspective, benefits accrue when both are combined on one platform, as it takes their communication and collaboration capabilities to another level, even when they are on the move.

This solution supports multiple SIP accounts and multiple lines per handset. Each handset can map to any SIP account and each SIP account can map to any handset. You can set up hunt group modes, such as parallel mode, circular mode and linear mode. In parallel mode all the phones ring concurrently. Once the call is answered on one, you can then place calls from the others. In circular mode, all handsets ring sequentially starting from the one that answered the last call. In linear mode, all the handsets ring sequentially in a pre-designated order. Push-to-talk (PTT), a two-way radio type service, enables simple instantaneous and seamless voice communication with the push of a button. We can now carry out upgrades, updates and change settings wirelessly over the air.

Let us now look at products from Grandstream Networks, a provider of DECT VoIP solutions.

Grandstream Networks DP752 Base Station features include:

• 1.9 GHz DECT 6.0
• Outdoor/indoor range: up to 400m/50m with DP730 handset and up to 350m/50m with DP722 handset
• Up to five DP DECT handsets per base station
• 10 SIP accounts and 10 Lines per handset, each handset can map to any SIP account and each SIP account can map to any handset
• QoS support: Layer 2 QoS (802.1Q, 802.1P) and Layer 3 QoS (ToS, DiffServ, MPLS)
• DECT pairing/paging button
• Five concurrent calls
• Voice codecs: G.711μ/a-law, G.723.1, G.729A/B, G.726-32, iLBC, G.722, OPUS, G.722.2/AMR-WB (special order), in-band and out-of-band DTMF (in audio, RFC2833, SIP INFO), VAD, CNG, PLC, AJB
• Upgrade/provisioning: firmware upgrade via TFTP/HTTP/HTTPS, mass provisioning using TR-069 or AES encrypted XML configuration file
• 10/100 Mbps auto-sensing Ethernet with PoE, IEEE802.3af Class 1
• Three LED status indicators for power, network, DECT
• Three-way audio conferencing and push-to-talk button for instant voice communication between the DECT phones  
• Hunt group modes-parallel mode, circular mode, linear mode
• DECT authentication & encryption
• Supports SIP server redundancy and failover

Grandstream Networks DP730 wireless IP phone features include:

• 1.9 GHz DECT 6.0
• Outdoor/Indoor range up to 400 meters/up to 50 meters
• 2.4” color LCD screen, 3.5mm headset jack, proximity and accelerometer sensors, 3-color MWI LED, Micro-USB port
• HD Audio on handset and speakerphone
• Software Upgrade Over-The-Air (SUOTA), handset provisioning Over-The-Air
• DECT authentication & encryption
• Up to 10 SIP accounts and 10 lines per handset, 3-way audio conferencing and push-to-talk button for instant voice communication
• Codecs:G.722 codec for HD audio and G.726 codec for narrow band audio (G.711μ/a-law, G.723.1, G.729A/B, iLBC and OPUS are supported via companion base station), AEC, AGC, Ambient noise reduction on handset mic, advanced noise suppression for incoming audio  
• 500 hours of standby time and 40 hours of talk time

Grandstream Networks DP722 wireless IP phone features include:

• 1.9 GHz DECT 6.0
• Outdoor/Indoor range up to 350m/50m
• 1.8” color LCD screen, 3.5mm headset jack,3-color MWI LED, Micro-USB port
• HD Audio on Handset and Speakerphone
• Software Upgrade Over-The-Air (SUOTA), handset provisioning Over-The-Air
• DECT authentication & encryption
• Up to 10 SIP accounts and 10 lines per handset, 3-way audio conferencing and configurable push-to-talk button for instant voice communication
• Codecs:G.722 codec for HD audio and G.726 codec for narrow band audio (G.711μ/a-law, G.723.1, G.729A/B, iLBC and OPUS are supported via companion base station) AEC, AGC, Ambient noise reduction on handset mic, advanced noise suppression for incoming audio  
• 250 hours of standby time and 20 hours of talk time

Let us now conduct functional and interoperability testing of the DP752 base station along with the DP730 and DP722 wireless IP phones.

FUNCTIONAL TESTING

The test setup will consist of the Grandstream Networks DP752 DECT VoIP Base Station with the DECT wireless phones DP 730, DP 722 running software release version: Version 1.0.9.1 and the following devices and systems (Please refer to Fig. B): 

• Public SIP trunk services;
• Patton SmartNode SN5570 Series eSBC (Enterprise Session Border Controller) running software version Trinity 3.15.1-19021 will provide SIP registrar services and SIP demarcation from the public SIP trunk provider while maintaining interoperability and interconnectivity;
• Microsemi PDS-208G Digital Ceiling PoE switch with software release version 2.53 for efficient network connectivity and PoE delivery.

Fig.B: Functional and interoperability testing of Grandstream Networks DP752,  DP730 & DP722

We plugged the PoE-enabled DP752 base into the Microsemi Digital ceiling PoE switch, which provided both PoE and network connectivity. We used the web interface for all the management and provisioning of the DP752.

As shown in Fig.C, it presented us with tabular options such as: STATUS, PROFILES, DECT, SETTINGS, MAINTENANCE etc.

Fig. C: Grandstream Networks DP752 Base Station - Web Interface

In this test setup, the Patton SmartNode SN5570 eSBC will provide the DP752 base station with SIP registrar services, SIP demarcation and access to the SIP trunk in the cloud. We configured values relevant for our testing by clicking on: Settings >> Network Settings >> Basic Settings [IP Address mode, Preferred DNS Server, IP Address, Gateway etc.] (refer to Fig.D). Then we moved to Profiles >> Profile 1 >> General Settings [Profile Active, Profile Name, SIP Server, Failover SIP Server, Prefer Primary SIP Server, Outbound Proxy, Voice Mail Access Number] >> Network Settings >> SIP Settings >> Audio Settings >> Call Settings (refer to Fig.E). We clicked on DECT >> General Settings [Base Station Name] Handset Settings [Handset Names] >> SIP Account Settings [Account 1, SIP User ID, Authenticate ID, Password, Name, Profile, HS Mode, Account Active] >> Handset Line Settings [HS 1 Line 1 & HS 2 Line 1] etc. (refer to Fig.F).  

We saved and applied all the changes that were made, then turned on the DP730 handset and selected the Subscribe softkey and selected Base. it started searching for the base station. In the interim, on the web interface of the DP752 under Status, we clicked on the wireless icon for Open subscription. It displayed the message, “subscription window opened.”

The DP730 now showed us our base station named Juno and we selected subscribe.  It said easy pairing, and then the handset was subscribed. We repeated this procedure for the DP722. The DP730 and the DP722 were now successfully registered with the DP752 and ready to place and receive calls as shown in Fig.C. The whole setup was very streamlined just a few clicks on the relevant screens, thanks to the well laid out DP752 web interface for configuration and management.

Fig. D: DP752 Base Station-Settings Page

 

Fig. E: DP752 Base Station-Profiles Page

 

Fig. F: DP752 Base Station-DECT Page

We tested the push-to-talk (PTT) feature of the DP730 and the DP722. The DP730 already has a physical dedicated PTT key. For the DP722, we programmed the left soft key as the PPT button. At the touch of a PTT button, it enabled us to establish a PTT session between the DP730 and the DP722 as shown in Fig.G           

                 

Fig. G: Display during a PTT session on the DP730 and DP722 

We liked the PTT feature on the DP730 and the DP722, as we could establish a speedy voice session with the other party without any need for dialing, ringing and waiting for the called party to pick up and answer. If a voice call was in progress, attempting PTT at that time did not impact the voice call which was in progress. Further an incoming voice call took precedence over our PTT session that was in progress.  We also turned the active SIP profile OFF so that the base now had no SIP registration…however in this instance the PTT session continued to work flawlessly.

To test the hunt group modes, we went to DECT >> SIP Account Settings and for our account changed the HS mode to parallel mode, circular mode and linear mode, each time the mode that was setup, worked as expected.  We were able to upgrade the software on the base station and the phones wirelessly over the air as shown in Fig.H.

Fig. H: DP752 Base Station- Status Screen

As soon as you log into the DP752 web page, it shows you the status, you are presented with information such as Account Status, DECT Base Status, DECT Repeater status, Line Options, Network Status, System Info etc. We could click on each of those respective tabs for further action and more granular and useful information. From one easy to access location these options gave us visibility and control into the configurational and operational aspects of the DP752 and the subscribed handsets. You could also click on actionable icons such as reboot, unsubscribe individual/all handsets, page individual/all handsets etc. Our functional and interoperability testing was successful, demonstrating to us, that the DP752 VoIP base station along with the DP730 and DP722 wireless phones are a feasible DECT solution to provide mobility, good voice quality and security for our enterprise telephony applications.

Conclusion

Grandstream networks DP730 and DP722 DECT wireless IP phones connecting to the strategically deployed DP752 DECT VoIP base station will deliver dependable wireless voice communications.