Neal Younger
TG582 Telnet
Busy Lamps with Gradwell and Cisco SPA series IP Phones
In Q4 of 2020 Gradwell announced their next phase of service, Multi-User-Voice-Plus, or MUV+ for short. The new platform benefits advertised as being able roll out new features faster - such as the long awaited Busy Lamp Field. I know a customer who has been asking for this since 2007!

How do I set it up?
Good question! Especially if you have comething like a Cisco SPA509G. There are articles for Snom, YeaLink, etc. But not Cisco models. It is a difficult one to crack. However after lots of packet capture, trial and error, it has been set up and seen working alongside a snom as a reference.
Prep Work
Latest firmware - this was done on a Cisco SPA509G phone running 7.6.2g which stupidly reports itself as only running 7.6.2 so it looks older than, say, 7.6.2e - but it isn't.

The subscribing identity has to be set up on Ext 1, otherwise the phone doesn't send the SUBSCRIBE requests form the correct account on the phone.

Log in to the web interface, make sure you're in as admin with the advanced view from the top right links. Navigate to the Attentant Console tab, under General set the Server Type as Asterisk.

If you're trying this with a different ITSP you may need to add Attendant Key LED Pattern Serv Subscribe Failed LED c=g and Serv Subscribing LED c=g for when the initial status isn't sent, and the phone assumes the key colour until it gets an update.
If you don't have the Expansion Module and want use and available phone Line Key:
On the Phone Tab find a spare Line Key. Extension = Disabled, Shared Call Appearance = private.

And so for the first extension/use you with to monitor - i.e. NOT your own extension number!:

Extended Function: fnc=blf+sd;;nme=DisplayName;

You can repeat this similarly to fill up any more unused Line Keys and phones you need to monitor.

You can probably tell from the acronyms that the keys will be both a Speed Dial as well as BLF indicator.

If you do have the Expansion Module(s):
Starting at, say, Unit 1, Key 1 set extended function as:


For example to have extension 2125290 as monitored, and a speed dial for Barry.

That's it!
You must use the full 7-digit extension number (even if you're used to calling only the last 3 digits internally etc.). This information is provided in good faith, but could be incomplete or inaccurate, use at your own risk.