VoIP Resources VoIP Reviews Softphones

Groundwire (v1.5) Softphone Review

by OnSIP

Groundwire is the business version of the Acrobits softphone application for the iOS. Read our performance review here.

Published: January 24, 2011


OnSIP Testing:star_orange_24star_orange_24star_orange_24star_orange_24star_orange_24
Voice Quality:star_orange_24star_orange_24star_orange_24star_orange_24star_gray_24
Ease of Use:star_orange_24star_orange_24star_orange_24star_orange_24star_gray_24

Quick Specs

  • Video, Conference Calling
  • Transfer and attended transfer
  • Multi line
  • Voicemail support
  • Call Forwarding


  • Design conveniently similar to native phone app
  • Highly customizable


  • Slightly more expensive than competitors
  • New - Video Calling
  • Multitasking background support for iOS4 and later
  • Transfer and attended transfer
  • Push Notifications
  • Multi line
  • Conference Calling
  • Voicemail support
  • Enterprise SMS support through SIP SIMPLE
  • SMS Support for betamax providers, pennytel and sipme
  • Call Forwarding
  • Web Callback and Call through for your native GSM number
  • GoogleVoice integration
  • Customizable ringtones
  • HD wideband audio through G.722
  • Simultaneous registration of multiple SIP accounts
  • iPhone contacts integration
  • Bluetooth support for iPhones iPad 2 and iPod Touch 4th Generation
  • Call recorder and player, seamlessly integrated into the call history

This review predates OnSIP’s mobile app for iOS and Android, free to OnSIP users, so is not affected by bias.

Acrobits is a mobile software company primarily focused on mobile SIP clients. Groundwire iOS is the business version of its Acrobits Softphone and is marketed as a viable replacement for desktop phones.

First Impressions

Groundwire’s UI design doesn’t stray far from the iPhone’s native phone app, making it familiar and all in all a visually pleasing experience.

This mobile VoIP app includes many of the components you would expect from enterprise VoIP software or SIP hardware devices. Features like multiple lines, blind and attended transfer, and conferencing set it apart from its sister app:

Groundwire Feature ListAcrobits’s website has helpful articles and tutorials.

Groundwire is priced at $9.99, with Bria for iPhone priced at .99 per month or $9.99 per year. (OnSIP’s iPhone app, by comparison, is free for OnSIP customers.)

Ease of Use

Groundwire is incredibly intuitive and easy to use. The upper left-hand corner has a status indicator, and the main navigation bar at the bottom has three main tabs: Quickdial, History, and Keypad. The fourth, Contacts, is merely an import of your native contacts.

Groundwire Screen Shot - Pick Contacts Groundwire Screen Shot - Call History Groundwire Screen Shot - Dialpad

The name of the currently active VoIP account appears next to the status indicator icon, which you can tap to switch accounts. If the icon is green, you’re registered. Green with two arrows means you’re taking incoming calls on that account. Red means you’re not registered, and there’s probably an error somewhere in your settings.

Groundwire Screenshot - Select Account

The Quickdial screen is simply a collection of your 12 favorite contacts, which you can tap to call.

History lists the call history for all of your VoIP accounts, and you can filter to only missed calls. Tapping the name within each list item automatically dials that number, while tapping the arrow brings up a screen with more detailed information about the call. It’s only here where you can find out which of your SIP accounts is associated with a particular call—absolutely necessary if you have multiple accounts.

Groundwire Screen Shot - Account Groundwire Screen Shot - Call Details

You can also access your call recordings here, and each call with an associated recording has a cassette icon next to it. You can listen to your recordings from your iPhone or email them to yourself.

The Keypad screen is your standard dialer with a SIP address input field at the top. It’s also home to Settings, where you can customize your SIP accounts as well as the look and feel of the app. Settings > Preferences leads you to a full list of customizable options. For example, you can enable the "Shake Gesture" to switch between active calls just by shaking your phone.

Call Experience

This is your screen during a call:

Groundwire Screen Shot - HomeYou’ll notice three options directly under the Caller ID info. The angled rectangle icon on the left takes you back to the main keypad screen so that you can make another call. Note: This does not put your current caller on hold until after you have dialed another number. The X-ed out microphone in the middle is your mute button, and the speakerphone is the far right icon. The latter two have indicators that show when they are active.

The center of the screen has six other call handling options. These include another keypad option (to interact with attendant menus), hold, call record, transfer, join (a conference feature that only works if you’re on two calls already), and attended transfer. The transfer and conferencing features are fairly intuitive. When you hit the transfer button, the app takes you back to the main keypad screen. Simply enter the number to which you want to transfer your caller and hit dial.

If you’re on two simultaneous calls, you can hit the attended transfer button. The app displays your other active call, which you tap to conduct an attended transfer.

Groundwire Screen Shot - Transfer
The join button to start a conference only works if you already have at least two calls going. If you do, hit the join button and you’ll be asked to select another party to invite to the conference. The app shows your other active calls, and all you have to do is tap on one. Once you’re in a conference you’ll see this screen:

Groundwire Screen Shot - Call Group Groundwire Screen Shot - Call Group 2

To transfer someone out of the conference via blind or attended transfer, simply tap the names of the attendees to select them individually.

Voice Quality

The voice quality on Groundwire is pretty good. With G.711 u-Law, the call quality is on par with what you get on a regular cellular (GSM) call.

Groundwire Codecs

The Groundwire app offers users the ability to select their preferred 3G and Wi-fi codecs. HD-G.722 is available for both. We found that calls negotiated in G.722 sounded much better, even while using our 3G network here in New York City.

Keep in mind that your overall call experience with Groundwire depends almost entirely on the network strength at your location. During a call, Groundwire displays a 5-bar scale that claims to measure the strength of your connection. You can also scroll to a screen (run your finger across the part of the screen with your call handling options) that displays the packet loss and jitter of the call.

JN Testing

At Junction Networks, we put each of the phones we use through a multi-step interoperability test in which we apply ~30 test cases. An example of a test case would be the following:

Test phone calls phone B

B picks up

B puts test phone on hold

B calls phone C

C picks up

B transfers test phone to C

The call must be transferred correctly to C. B must be released correctly after the transfer. When C picks up, audio must work in both ways between test phone and C. When test phone is on hold, there is no audio between it and phone B.

Groundwire version 1.5 passed our test cases with no issues, although we did notice that having Groundwire open throughout the day significantly drained the battery on the iPhone 3GS.

App Configuration

Here’s a quick rundown on how to set up an OnSIP SIP account on Groundwire. You’ll need your personal SIP credentials, which you can find in your user’s tab in the OnSIP admin portal. This is what you’re looking for:

OnSIP Configuration settings for Groundwire

In Groundwire settings, the first option listed is "SIP Accounts." Tap the plus sign to add an account, and select "Generic SIP Account." Enter your user credentials as follows:

  • Title - Your Choice
  • Username - Username
  • Password - SIP Password
  • Domain - Proxy/Domain
  • Display Name - Your Choice

Next, tap on "Advanced Settings" and scroll until you see "Auth User Name." Enter the Auth Username info you have from your SIP credentials.

Finally, scroll down even farther until you see "Outbound Proxy." You"ll want to enable it, set the "Host" to "sip.onsip.com," and make sure that the "Transport Protocol" is "udp." Hit "Done" when finished. These are the steps:

Groundwire SIP Settings Groundwire Auth Username Groundwire outbound Proxy

Acrobits has helpful video tutorials on its YouTube page

Intuitive, customizable, and feature-packed, Groundwire seems to be a promising addition to the growing number of enterprise-class SIP applications.

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