| This article was originally posted in June 2009, before Gizmo5 was purchased by Google. |
Whereas Skype is a relatively closed network using proprietary protocols and codecs, Gizmo5 is based on SIP, a global open standard. A Gizmo5 account can be used from the Gizmo5 soft phone client or any SIP compliant device. That means that the myriad of SIP phones (hardware & software varieties) can be used with Gizmo5.
Let’s presume that you’re just starting out so you elect to use the Gizmo5 soft phone (shown below, full size) It’s actually a nice piece of software. With it you will be able to dial other Gizmo5 users, SIP URIs and PSTN numbers (that is, normal phones numbers.)
Calling other Gizmo5 users might result in wideband calls. That is, if both you and the other person are using the Gizmo5 soft client. In building their client Gizmo5 licensed a codec library from GIPS, which includes some wideband capabilities.
Where soft phones like the Gizmo5 client are concerned all my prior advice about using a good headset or USB speakerphone still applies. If you want it to sound really good you need some decent hardware. It’s not expensive, and definitely worth the investment.
The ability to dial by SIP URI is a big advantage if you truly want to make the most of wideband calling. SIP is, well…y’know…SIP…the protocol at the root of most IP telephony. And URI means “Uniform Resource Indicator.” It’s a form of an address not unlike an email address. For example, sip:mgraves@mstvp.onsip.com is a SIP URI that rings the Polycom phone on my desk.
Go ahead and call it if you can, I don’t mind. If I’m not there you’ll get my voicemail.
Soft phones make it easy to dial by SIP URI since you’re already using a computer, so you have ready access to a keyboard. Traditional phones, lacking a full keyboard, don’t offer such convenience. Most business class phones will store SIP URIs in the phones contact directory (see below). As a practical matter this can be enough for most people, given that its also easy to store the URI arising from incoming caller ID into your contact list.
The big deal about dialing by SIP URI is that it spans service providers. Unlike Skype, where you can only call other Skype users via wideband, using Gizmo5 you can call any SIP URI…including users of other SIP services, like my OnSIP account. And all calls to/from SIP URI using Gizmo5 are free.
Incidentally, the Gizmo5 soft phone does not support G.722. This is a bit of a drag since most business grade IP phones support G.722 wideband calling. All the newer, CATiq certified cordless phones, like the Gigaset A580IP and S675IP, also support wideband calling using G.722.
You might wonder why I dwell on the G.722 so much. I think that it’s really important that we have interoperability between different devices and services. At the moment G.722 is the lowest-common-denominator of wideband codecs. It’s not ideal, but it’s more widespread than just about anything else, so for now so it’s what I prefer to use.
One of the advantages of Gizmo5 is that they let you bring your own SIP compliant software or hardware IP phones into the mix. This alters scope of possibilities considerably.
There’s nothing to stop you from using another SIP soft phone to access your Gizmo5 account. I recommend the latest version of Eyebeam for Windows and PhonerLite (shown above) as both are G.722 wideband capable, the later being freeware.
It’s worth noting that even a narrowband call placed over a pure IP network, like between Gizmo5 accounts, will sound better than a call placed via the PSTN. This is because the call path is more direct, and high quality IP phones tend to have great hardware properties. That is, the speakers and the microphones are better quality. This alone can make a big difference, even in narrowband.
You can dial normal phones from your Gizmo5 account. To dial PSTN numbers you must invest in some Gizmo5 credits. Like Skype, calling the PSTN from Gizmo5 is cheap but not free. Since the calls are being routed to the PSTN they will be negotiated down to G.711 narrowband in the best case.
This ability to use a diversity of hardware or software phones with Gizmo5 means that you never really know what the other person might be using to take your call. Thus you cannot ensure that your calls to everyone will be wideband. The best that you can do is leverage wideband automatically whenever possible.
Of course, if you have a wideband capable phone of any description then you might want to join in on a VoIP Users Conference call one Friday. We use the ZipDX wideband conference service which is available via SIP URI. See http://vuc.me for details.
