Groundwire: VoIP SIP Softphone

Review by eFreeware

If you already have a VoIP account or a company PBX and want it to ring on your Android phone, Groundwire is built for exactly that. It is a SIP client from Acrobits, a name in VoIP software, not a calling service of its own, so the number and the minutes come from a provider you arrange separately. What you get for a single $9.49 payment is the dialer, the call handling and the encryption layer on top.

That distinction matters more than any feature list. Groundwire does not sell you calls, and it will not work without a SIP account behind it. For someone who already has one, whether through a hosted business phone provider or a PBX in the office, the app is the piece that makes the account useful on a phone. For someone hoping to install it and start making cheap international calls, it is not the right tool.

The app has been on Google Play since April 2012 and shows over 50,000 installs with a 3.3 average across 732 ratings. Those numbers describe a mature, fairly niche tool rather than a mass-market calling app, which fits what it is: software for people who know what SIP means and have an account to point it at.

Call handling that mirrors a desk phone

The features the developer puts first are the ones an office phone would have. Group calls let several people join one conversation, which covers the basic conference case without a separate bridge. Attended transfers let you speak to the person you are handing a caller to before the call moves across, and unattended transfers push the caller straight to an extension when no introduction is needed. Between them, that is most of what a reception desk does in a day.

Voicemail with notifications means missed calls still reach you. Instant messaging covers the short exchanges that do not justify a call, which is useful when you are in a meeting or somewhere a conversation would be awkward. Per-account settings let one phone carry several SIP identities without them bleeding into each other, so a work line and a personal line can coexist.

I would expect this combination to appeal to someone who spends part of the week at a desk and part of it elsewhere. The transfers in particular are the sort of thing that feels optional until you are the person answering the main line and need to move a caller along.

Codecs, encryption and call quality

Audio runs on widely used codecs including Opus, G.729 and G.711, and video calls are handled at 720p through H.264 and VP8. Those are standard choices rather than exotic ones, which is the right instinct for a client that has to interoperate with whatever a provider already runs. If your PBX speaks one of them, the app should have something to negotiate with.

Encryption is included rather than sold as an extra: TLS, SRTP and ZRTP, described as military-grade, sit inside the purchase price. The developer also pitches encrypted SIP calling on every network, and that is the kind of claim worth treating as a promise rather than a guarantee. On some setups that is arranged; on others it may not be.

Two smaller details are more practical than they sound. Push notifications are used to keep battery drain low, which matters for an app that has to stay reachable all day. Calls can move between WiFi and mobile data mid-conversation, so leaving the office need not cut the call.

Fitting into the Android phone you already use

Groundwire leans on Android's built-in calling features rather than replacing them, which keeps the experience closer to a normal phone call. Audio is routed intelligently between the handset, the speaker, a wired headset and connected Bluetooth devices, so the app follows the hardware you have rather than forcing a choice. Grant permission and Groundwire calls show up in the Phone app's Recents, so there is one history rather than two.

Custom call settings and ringtones per account are a small thing that becomes useful once a single device carries more than one identity. A distinct ringtone for the work line tells you whether to answer before you have looked at the screen, and separate settings let each account behave the way its owner expects.

The most recent update listed is an improvement to Android telecom handling. The developer says it works on 5G networks and runs on nearly every mobile platform.

What Groundwire asks of you first

The requirement is unavoidable and the developer states it plainly: this is a SIP client, not a VoIP service, and you need service from a provider or PBX that supports standard SIP clients. Without that account there is nothing to configure and no calls to make. The app comes preconfigured for major providers, so setup is quick in that case, but you still need your own account and pay for it separately.

The app costs $9.49 once. There are no ads and no in-app purchases, and the developer's pitch is that the business dialer features which usually carry a monthly fee are covered by that single payment, with encryption included rather than added on top. Whether that works out cheaper than a subscription depends on what you are comparing it with, but the structure is simple: one payment, no tiers.

Standards-based, so you are not tied to one vendor. Your existing account is all you need; the app then acts as the mobile side of your PBX. It serves as a softphone for Asterisk, FreePBX and 3CX setups, and works with hosted PBX services and business phone carriers. That flexibility is the point of a universal client, and it is also why the app cannot do anything for you until an account exists.

Getting the most out of a SIP account on a phone

The sensible approach is to settle the account first and the app second. Confirm what your provider or PBX supports, then add the credentials and check that a basic call connects before worrying about transfers or video. If your provider is one of the major ones the app comes preconfigured for, that step should be quick.

Once calling works, per-account settings are worth a few minutes of attention. Giving each identity its own ringtone and call behavior makes a multi-line phone readable at a glance, and it prevents the confusion of answering a business call as if it were personal. If you handle a main line, learning the two transfer types before you need them is the difference between a smooth handover and an apologetic caller.

For anyone running several extensions, the same app is described as covering a call center, a fleet of extensions or a single home office line, with no extra tiers to buy. That is a claim about scope rather than a promise about scale, and it is worth reading as such: the app is one client, and how well a large deployment works will depend on the PBX behind it. Support is described as responsive, which matters if a provider's configuration turns out to be unusual.

A one-time purchase for people who already have SIP service

Groundwire is worth installing if you have a VoIP provider or PBX account and want it on your Android phone without a recurring app fee. The transfers, conferencing, voicemail notifications and messaging cover the desk-phone basics, the codec and encryption support is standard enough to interoperate, and the integration with Android's calling features keeps it from feeling like a separate world. At $9.49 with no ads and no in-app purchases, the cost is easy to understand.

The 3.3 average from 732 ratings is a reminder that this is specialist software. The requirement is the whole story: no SIP account, no calls.

I would point this at the person who already pays for a business line and wants it to follow them, or who keeps a work number separate from a personal one on the same handset. If that describes your situation, the single payment and the absence of tiers make it an easy thing to try.

What's new in version 26.1.31

- Android telecom improvements