We get asked about this a lot. This is a slightly cleaned up and generic version of an email I just sent out. Seems I sent something like this out once a month or more. It was time to add it to the Wiki.

John,

We feel your pain with the basic Grandstream WP720/750 combo's. We stopped promoting them on our website… enough said? They work… mostly… the base box (the WP750) goes brain dead. It needs rebooting. We've seen better results with the newer WP752 base station, even with the older phones. Once subscribed to a new base they'll update firmware which will help. And even newer firmware on the WP750 may help. But.. they aren't my fav.

The Yealinks work a lot better than the Grandstreams as a DECT phone. There is even a high end version of the Yealinks for campus wide roaming across base stations (W80). But the W60 and W56H I have at home works well. I wish it had a better “clip”, I put a lanyard on it and use it when working from home outside. It's got great range. I hate the 2.5mm headphone jack… but as a phone it works very well and has good sound for a small handset. We have other customers using them and they are not getting negative comments like we have with the Grandstream 750/720

Next interesting option is a GrandStream WP820. Once configured, this Android based WIFI (no base station) phone is awesome within your wifi coverage area. We have one in the office and it's what gets used when out and about in the office. We are in a commercial metal building, it does not reach our parking lot. Sound quality is very good and it works like a good VoIP phone should. Transfer, hold, etc.. features work well and it has a standard 3.5mm headphone jack.

We have issues getting them to configure sometimes. They go to deep sleep when not configured and we have to get someone to fiddle with the buttons to keep them awake. Once configured they are fine as they don't go to deep sleep. They can also be manually configured easily.

WP820's last over a weekend not plugged in.. If you have good WiFi coverage (and not a “mesh”) these are awesome. Our office has Ubiquiti AP's, but any good WiFi AP should work well.

You asked about the Cisco 8821. I've never seen a Cisco 8821, not even sure if it handles generic SIP in all flavors. If it does generic VoiP SIP then it will work, it'll just be an experiment figuring out a few settings. It's usually extension #, SIP server (Hello Hub) IP Address and a password. Cisco's sometimes need a few extra boxes checked. If you want to try, we will help.

Same goes for any wireless VoIP phone. If it'll do industry generic SIP/VoIP, it'll probably be working in 5 minutes. Maybe 10 if we chat a lot.

Other mobile options: Generic “POTS” wireless phones plugged into a Grandstream HT802 ATA (POTS) phone adapters and cheap android phones mobile phones on WiFi using a VoiP “app” like Grandstream Wave or Zoiper. There are a lot of ways to make good dedicated wireless phones work. –Mike–