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Cisco 7940 setup

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K5DLQ's picture
Cisco 7940 setup

Here are my brief notes on configuring for a 7940:

(comment: nice hardware, EXCEPT, there's no backlight, which may be a problem for EMCOMM.  Will probably stay with the Grandstream GXP-2000's.)

Configuring a Cisco 7940 IP Phone for Asterisk


This assumes the following:

  • You have a tftp server installed somewhere (ie. raspberry pi)

Factory reset phone

  1. Unplug the power cable from the phone and then plug it back in. The phone begins its power up cycle.

  2. While the phone is powering up, and before the Speaker button flashes on and off, press and hold #. ...

  3. Release # and press 123456789*0#.

Configure DHCP to deliver the TFTP server

On the local AREDN node:

  1. Edit the file: /etc/dnsmasq

  2. Add this line:   dhcp-option=66,"IP-OF-YOUR-TFTP-SERVER"

  3. Save the file

  4. Reboot the node (or /etc/init.d/dnsmasq restart &)

Add files to the TFTP Server root

(3CX provides some of these)

  1. P003-8-12-00.bin

  2. P003-8-12-00.sbn

  3. P0S3-8-12-00.loads

  4. P0S3-8-12-00.sb2

  5. Add the file SIP<MAC ADDRESS OF PHONE>.cnf with the following lines:

line1_name: 1000

line1_authname: 1000

line1_displayname: Your Name

line1_password: “yourpassword”

line2_name: 2000

line2_authname: 2000

line2_displayname: Your name

line2_password: “your password”

** If your 2nd line is on a different PBX than the default, add:

proxy2_address: IP.OF.2nd.PBX

  1. Add the file SIPDefault.cnf with the following lines:

image_version: P0S3-8-12-00

proxy1_address: IP.OF.1st.PBX

proxy_register: 1

messages_uri: *97


Add an extension in the PBX

(no instructions here since the techniques may vary)

Reboot the Phone

    * 6 SETTINGS

** FYI, Freepbx auto-generated passwords are too long!  You must shorten it!

Polycom SoundPoint phones possibly a better option?

I've done a lot of work over the years setting up and testing various SIP based VoIP phones, both for ham hobby use and commercial installations.  For a deployment of only a few phones I've found nothing to beat the Polycom SoundPoint phones.  The biggest advantage I see is that no TFTP server is required to deploy them, and no fancy mods to DHCP.  This saves a lot of unnecessary hardware and headache running on the mesh (or any other network where you need to deploy VoIP devices).  You configure parameters directly in the phone via a web interface, and only 4 or 5 parameters are necessary to get the phones up and running.  For low cost I've used the SoundPoint 32X and 33X series, with the 335 phone also having a backlight.  Grandstream and SNOM are good phones too, but the Polycom SoundPoint 300 series are pretty rugged, readily available from the usual sources for reasonable prices, and can be powered PoE or locally with a 24 volt power supply.  But my feeling is all of these options are better than the Cisco 7940 series, as no firmware mods are needed to support SIP and most can be configured manually to avoid the TFTP server nuisance. Clearly where large numbers of phones need to be deployed a TFTP-based installation (with DHCP support for Option 66 or 150) is almost a must (which the Polycom phones do support).  But for someone deploying only a few phones, the manually-configured Polycom SoundPoint phones are hard to beat.

73, Bill, N4SV

Polycom IP 330
Hi Bill,

I'm new to AREDN and Voip phones.  I have a Polycom IP 330 that I've been trying to configure to direct ip dial on the local AREDN mesh network. I saw in your post that "only 4 or 5 parameters are necessary to get the phones up and running."  I haven't been able to figure out what those 4 or 5 parameters are. Can you give me some pointers on getting this thing configured?

K5DLQ's picture
Great feedback Bill, thank

Great feedback Bill, thank you.

That's one thing (ok, three things) I do like about the Grandstream's as well: a decent web based ui for config, good backlight, and you can run from 5VDC.


Phones like the SNOM 300 also

Phones like the SNOM 300 also use 5 volts which is nice because these power supplies are readily available in the $10 range.  Thanks for the complete set up on the Cisco 7940, I can't tell you how much time I spent piecing all that together when I was setting up some 7940s on an Asterisk-based system.  And trying to slog thru the Cisco documentation is extremely uncomfortable.  Having all the info in one place will help folks who have access to these phones make them useful in a SIP environment.  Thanks.

73, Bill, N4SV

Smaller VOIP Phone options

Am reading this thread with interest as I'd like to find a simple VOIP phone option for mesh. The phones mentioned here are somewhat large for packing up and taking out into the field. Are there any VOIP phones that are small and support SIP?

Mark K5LXP
Albuquerque, NM

KE2N's picture

If you still want a desk phone then there are smaller ones (with no display) and they are relatively cheap.  One neat trick of the GrandStream phones is direct IP to IP calling with no server.  For a simple setup or demo that is convenient.

If you want really small, Google cordless IP (or VOIP) phone. You will need an wireless access point (WAP) for this.  Having set up a WAP you will find you can access it with your smart phone too.  There are numerous SIP (and some asterisk) clients for smart phones.

The only issue I found with one cordless IP phone I tested was that it did not have much audio - not good for noisy areas. 


Smaller IP Phones

Another option is to use a Grandstream HT701 and then you can use ANY analog phone.  So you can chose a small one. I find use of AT&T analog phones is best, because their dialing memory is long enough to make speed dialing possible with the typical long IP address.


ATA use
While using an ATA is one option, it does make the deployment a bit more cumbersome, another device, another power supply, more wires, and of course the analog-to-digital conversion issue.  I've used the Linksys PAP2-T ATA and it works OK (usually when something like an analog FAX system needs to be added to an existing VoIP installation), but occasionally has issues passing DTMF properly.  Going with something like a Polycom IP 321 or SNOM 300 and you eliminate the A-to-D issues of the ATA and keep the installation relatively simple and clean.  But a good point that with an ATA, any analog phone can then be used..although finding analog phones that don't have a lot of potentially unnecessary things added in like answering machines and such is getting harder and harder to do, HI.

73, Bill, N4SV
K6AH's picture
SIP Phone Alternatives

Not to get too far away from the original question... but you could also use a BYO, WIFI-connected, cell phone running one of a number of SIP apps.

Andre, K6AH

K5DLQ's picture
absolutely.  I use an

absolutely.  I use an AirGateway (to bridge wifi->mesh) and Bria softphone.  works well.

WU2S's picture
Voip app Linphone

Also works well with Linphone app on iOS. Test with both AirGateway and Linksys bridge to mesh. Used during recent Red Cross exercise.

Cisco 7941 supported?

I see that Cisco 7940 and 7960 are partially supported. Does that include the 7941 also?

I am assuming that the 7940
I am assuming that the 7940 does not support direct IP calling, correct? 
7940 / 7960 XML Service Apps

I whipped up an Incredible PBX implementation on a RPi 3 a few weeks ago and put it up onto my Aredn mesh.  I have Cisco 7940 and 7960 provisioning working well.  My nodes are set to push TFTP info from DHCP (Can one of these firmware updates get that built into the Web UI for the nodes?? Maybe a blank field to fill in other advertised service ports from the DHCP server?).  All that just plain works.  I'm experimenting with codecs across the mesh and tunnels.  I'm experimenting with jitter.

I took a break last night to install and configure Open79XX and have created XML directory and enabled the service button on the phones.  I also had a little bit of time to kill and threw together two XML apps in PHP.  They both use fopen to pull down URLs to parse from text to XML format that the phones need.  If anyone is interested in a copy of the PHP code for the apps, I'd be happy to post it here.  

The first app pulls up our local airport's decoded METAR and display's it to the phone formatted mostly like:

Jun 13, 2017 - 07:54 PM EDT / 2017.06.13 2354 UTC
Wind: from the N (360 degrees) at 8 MPH (7 KT):0
Visibility: 10 mile(s):0
Sky conditions: mostly clear
Temperature: 72.0 F (22.2 C)
Dew Point: 62.1 F (16.7 C)
Relative Humidity: 71%
Pressure (altimeter): 29.99 in. Hg (1015 hPa)
Pressure tendency: 0.01 inches (0.3 hPa) higher than three hours ago
ob: KBUF 132354Z 36007KT 10SM FEW060 FEW140 FEW300 22/17 A2999 RMK AO2 SLP152 T02220167 10278 20222 52003
cycle: 0

The second app pulls in the current solar indices and displays it mostly like:

Geophysical Alert Message

2017 Jun 14 0005 UTC

Solar-terrestrial indices for 13 June follow.
Solar flux 75 and estimated planetary A-index 8.
The estimated planetary K-index at 0000 UTC on 14 June was 1.

No space weather storms were observed for the past 24 hours.

No space weather storms are predicted for the next 24 hours.

Neither one requires any special libraries or includes to run, just access to fopen.

I'm revamping some of my code from my webpage in Perl to be able to do a QRZ search from the phone itself on the service page as well.  That will require a few Perl modules for it to work so it's not as easy to install and isn't finished yet.

If anyone wants any of the above posted, let me know.  It may work with other Cisco phones but I can only test 7940/7960.

Gary, N2WLS

Cisco WIP310
Is the Cisco WIP310 Iphone useful with AREDN?   With or without its accompanying SPA9000?


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