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DECT Wars: snom m3 vs Siemens S685IP

If you’ve been hanging around these parts a while you’ll already know that I’ve had the snom m3 SIP DECT phone system installed since mid-January. I got lucky and bought one of the first units delivered to snom’s US distributor in Dallas.

Then a few months later, and after hearing rave reviews from a few people abroad, I imported a Siemens S685IP SIP DECT phone system from the UK. So now we have two SIP DECT systems on the property.

Why you ask?

Neither is quite a complete solution. There’s something missing in each case, and I wasn’t able to determine this fact from the specs alone. It wasn’t until I laid hands on the hardware that the problems became evident.

In this DECT war we’re not yet declaring a winner around our house. We’re actually closer to declaring two losers. Funny how apparently little oversights can completely sink a product.

Both phones work great with Asterisk. Both also work well with our hosted PBX provider, Junction Networks OnSIP.

We have at least two handsets for each system and find that calling behavior internal to the system is about the same. You can take a call on one handset, transfer it to another without involving the PBX. Common calling features like hold and conference work about as you’d expect.

Both phones have really good cordless range. Better than any Wifi phone I’ve tried.

Both phones sound pretty good, too.

So what’s the problem you ask?

Let’s start with the snom m3.

The snom m3 has been our primary cordless phone these past seven months. It gets the most daily use. It’s one problem is that there’s no way to load contacts into the phones dialing directory.

I know, this sounds like a little thing, but it’s not. Our legacy 7 year old Panasonic KSU has 100+ family and friends loaded into the handsets. It can even copy contact lists from the base to the handsets and vice versa. My Aastra 480i CT could do this, too.

To decommission the Panny I have to get all those contacts loaded into the snom. Not once, but twice…once in each handset. Three times if I add another handset, which I’d have to do to replace the Panasonic system. And loading contacts by hand is really, really tedious and time consuming.

It’s simply an oversight on the part of the manufacturer that uploading a contact list isn’t possible. Heck, the phone has a web interface. You ought to be able to provision a contact list from a csv file, or vcards.

Remember, snom aim to sell these to businesses. The phone is already on the network, it ought to be able to pull contact details from an LDAP server. Now THAT would forward looking.

Now on to the Siemens S685IP.

I had really hoped that this phone would be a more complete answer as it has the contact list matter completely solved. Using the web GUI it can import a contact list from a vcard file in a heartbeat. Wow! That was great.

It supports G.722 wideband calling, too. Wow! That’s really great!! In fact it was the one thing that compelled me to buy the phone. Even importing it from the UK.

But it’s also really annoying in a few critical ways.

Firstly, there’s no mute function for the microphone.

What? No mute?

You’re kidding right?

Yeah, no mute.

That’s a major pain if you’re using the phone for business. Y’might not think so, but it’s really is inconvenient.

I frequently take part in long conference calls. I clip the phone onto my pocket, wear a wired headset and continue to do stuff while on these calls. That I can’t locally mute the mic means that everyone on the call hears what I’m doing.

They hear when I visit the coffee machine and pour myself some joe. They hear me later when I take every sip. They hear me typing.

Many conference bridges have some form of automatic gain control. If you’re not speaking, and not muted, they actually ramp up the gain on your line. Thus, when you have been quiet for a short while and you start typing everyone on the call hears your keyboard clatter…really loudly, like hail on a tin roof.

Now it’s true that many conference services have server-based muting, often on *6. This is certainly the case with the Talkshoe bridge that we use for the VOIP Users Conference calls. Also on others that I use. But even so, this is less convenient than it should be.

When you press *6 to engage the mute the bridge interrupts the call for a few seconds to tell you that “you are muted.” Duh. I know. I did it.

Later, when you want to unmute it’s two keypresses again, then wait for the message…then talk. ARGH!

The snom has a soft button assigned to mute/unmute when in a call. Even the aged Panasonic handsets have a mute feature, on that most prized of things…a dedicated button!

Not having a local mic mute is a serious problem.

Further, the phone is very Euro in nature. Now this is not completely its fault. I did import it from the UK. It is made by a German manufacturer specifically for the European market. They don’t even offer them in the US. Mea culpa.

But it’s selection of ring tones is very strange. There’s nothing even close to a North American ring tone built-in. There are a number of lovely melodies that would doubtless bring a smile to an Austrian composer or German trance or techno-fan.

Finally, the phone has its own built-in music-on-hold. When you put someone on hold, or start to transfer a call, the other party is going to hear a completely regrettable MIDI-like melody. And you can’t turn it off.

In the case of the Siemens phone I must admit that I’m overlaying my requirements onto something that is very clearly intended as a consumer device. It’s not designed as a business phone. Cutesy music-on-hold may be a feature at home, but it’s embarrassing in the office.

Pity. So close, but no cigar.

I’d list the S685IP on E-bay and set it free, as I have done many IP phone in the past. But I’d feel uncomfortable selling it to someone in the US when it’s not sold or supported over here.

So there is no solid solution yet. The ancient Panasonic KSU remains in service in the house. We still use the m3 a lot, especially in my office where the lack of a contact list is not an issue.

I could be very satisfied if snom would release a firmware update that supported an uploadable contact list. But as snom OEM’s the device from RTX Telecom it’s unclear if they have such scope in the development of the firmware.

So eight months into the fight this DECT war has come to a stalemate with no clear winner. I’m considerably invested in this matter. I guess I just press on examining ever more SIP/DECT systems as they arise and hoping for the best.

This Post Has 30 Comments
  1. Hi,

    I really enjoy reading your blog, I’m directly from snom, to address your wishes, in the next FW Version we plan to have a phone book push to the handsets (v 1.17).

    We were able to greatly improve the resources on the m3 so you might look forward for more cool features coming up.
    The m3 is based on RTX OEM, but it has greatly been changed from FW side, any other RTX based phone will never achieve the same feature set we have at the moment.

    Just one annotation, be careful with importing DECT based equipment from Europe. US/EU DECT equipment have to use different frequencies (frequency: 1880 MHz–1900 MHz in Europe, 1920 MHz–1930 MHz in the US, source Wikipedia).
    The European Frequency range is reserved for the military in the US and the US frequency may interfere with 3G networks in Europe, both things you might avoid (this could become expensive).
    This is nothing we have chosen this comes from the local regulatory authorities.

  2. Tim,

    Thank you very much for responding! That snom is paying attention is a very good sign. Some months ago I filed my observations with yourselves and ABP Technologies as a new feature request.

    I look forward to the firmware update you mentioned. Any ideas when it is projected for release?

  3. Hi Michael,

    we know that we would like to have more cool features sooner, due to some bug fixing and newly increased development ressources, I’m positive that new stuff will come faster now.

    We’re planing to release V 1.17 beginning of September, as usual there might come up something uncalculated which pushes the release date into the past. But you can be sure that we’re working hard on this new release.



  4. I just received an M3 base station and a single handset today. I have an old Panasonic multi-handset cordless system that I am planning to replace with the Snom M3. This is also my first experience with VoIP. I set up an account with Callcentric and got it working pretty quickly, after realizing that I had to reboot the Snom system after I made all of the config changes I needed. I have been considering setting up an Asterisk system, but just connecting the Snom to Callcentric directly meets most of my needs. The only complaint I have, and at this point the only reason I might still consider building an Asterisk box, is that I have to use 11-digit dialing for every call. If the Snom phone would allow me to set up a simple dial plan, i.e. add a 1 to the beginning of a 10 digit number and add a 1 plus my area code to a 7 digit number, I would be completely happy with my Snom+Callcentric solution.

    Any chance that Snom might add such a feature in a firmware update?

  5. Yes, something like the “digit map” feature in a Polycom phone would take care of your 10/11 digit issue.

    OTOH, a small local Asterisk (or Freeswitch) box is going to give you massive flexibility. In particular, the ability to cascade between VOIP providers automatically if one should become unavailable. In my case it lets me select to route the call out via one of 3 VOIP providers or to my GSM gateway and out through a cellular trunk.

  6. Incase Tim is still checking in… any chance we’ll see G.722? That’s the only thing stopping me from buying the M3.

    And thanks for the very elucidating comparison! I was ready to pull the trigger on the Siemens until I saw that bit about the hold music and mute button.. GEEZ!

    For people interested in PBXs… I’ve been developing on Freeswitch.. LOVE IT… one neat thing you can do is stream shoutcast into conference rooms or on hold.. Nifty!

  7. I’ve had my S685IP now for a week. If you want to turn off the completely regrettable hold music, there’s an option for this. Menu->Settings->Base station->Hold melody (or something like that – I’m translating from the German version here).

    As for not having a normal US melody – you can add your own ringtones, so fixing this shouldn’t be too big a deal.

    Finally: the feature I most like is the ability to display information as part of the screensaver. It’s unfortunate that Siemens have made so little of this. They can show weather info, they can show the first line of the first item of some RSS feed, and that’s it (we’ll skip over the Biorhythms and Horoscope, which are as regrettable as the hold music).

    To this end, I’ve written a script to deliver my own data to the handset. You can get it here:

    To get this to work, you’ll need to be running your own DNS server and your own web server. Assign the S685IP to point at your DNS server with a static IP (if need be). Make your DNS server authoritative for and point that at the IP of your web server. Set up a vhost for Create a directory info and put the script in there. Presto, you have an easily modifiable script which can display various different pages of useful information and can do so time-controlled. Mine shows local weather, a couple of news sites and pulls up whether the train’s going to be punctual in the hour before I have to pick my girlfriend up from the station…

  8. …and to correct my earlier statement, it seems that I was deluding myself whenI said that you can add additional ringtones to the S68H (the handset that comes with the S685IP). You can’t.

    Another thing the S68H can’t do: assign different ringtones to different incoming numbers. We have three numbers here. It was extremely useful with my previous system to be able to audibly tell the difference between a call for me and a call for my girlfriend.

  9. I have been using the siemes S685 and its predecessor for the past year or more. my biggest gripe is the speed [or lack thereof] with which the handset responds to keypresses.
    Perhaps i am too type ‘A’ but i regularly find myself waiting for the phone to catch up.
    the panasonic (yup, got one here too) on the other hand performs remarkably well in this respect.

    what is your perception of the Snom M3’s performance by comparison?

  10. Well, I broke down and set up a Asterisk box to sit between Callcentric and my Snom M3. After a couple of days of learning, I have everything working, except that the Snom doesn’t want to take any incoming calls from the Asterisk box. I can call out, I can call in to a softphone (X-Lite), I can call from the Snom to the softphone, but I can’t call the Snom from an outside line or from another extension. Is there some magic tweak to the Snom or Asterisk config? I found a reference to a problem with other Snom phones and older versions of Asterisk (Support broken registrar) but that doesn’t exist in the M3 config that I can see.

  11. Great comments on this site – Just board 4 x Gigaset S684 from the uk – and trying to find the right Power Adapters – where did you find yours?

  12. I bought universal power supplies from Fry’s locally here in Houston. They did not have the right connectors for the phones so I had to splice them into the low voltage wires.

    Beware though, I may have damaged a couple of the handsets by sending them slightly too high a voltage. Two of them no longer charge their batteries when in the base.

    You may be better off to buy step-up transformers to make 220vac from your line. Then you can plug-in the manufacturer supplied wall warts. Such transformers are sold at better stores like Fry’s or travel accessories/luggage places.

  13. Michael, I have difficulty setting up my snom m3 with 4 handsets with a trixbox based asterisk. Can you please share your setup and help with my problems.
    I opened a thread over at the smallnetworkbuilder forum.
    Thanks in advance, L.

  14. I’ll go back into my Asterisk box and have a look at things later today. Bear in mind that I don’t user Trixbox. I use Astlinux, which is more like a basic Asterisk installation.

  15. Thanks a lot.
    That’s fine, as long as I have an idea how you have set it up in Asterisk, I can play around in Trixbox. Trixbox also uses Asterisk with FreePBX gui to modify settings.
    Specifically I am interested in how many extensions and voicemail boxes you have set up. L.

  16. The Snom M3 is a great phone. A couple of things that are lacking – phonebook uploads as mentioned already. Also a keypad lock would be fantastic. Offten hitting buttons, and sometimes powering the phone off without realising it.

  17. I just checked and the mic mute function is NOT present on the left soft key while on an IP based call. It may be on a “external” call, which I take to be an analog call.

    The left soft key is labeled “Ext Call” when on a IP call.

  18. It’s the left side of the control key (marked “INT”) to mute, not the left soft-key. Although this is not mute in the sense that I expect and would prefer. The microphone is muted but incoming audio is also muted, so it is useless for blocking local noise on a conference call.

  19. In the end the S685IP is a good phone for home use, but not well suited to business applications. To many little gotchas/annoyances that at home would be ok, but in the office make it a non-starter.

  20. Just in case other prospective buyers of the Siemens S685IP are put off by the lack of a Mute option, I have just bought a set and can confirm that Mute functionality IS now there for both fixed and Voip calls via the latest firmware update as issued 04/2009 (Version: 02184).

    As it says at :

    “Mute function. Turn off the handset’s microphone during an external call with the left display key”.

    I have tested this and it works as a normal mute for both fixed lien and Voip calls. So loks like Siemens are good at taking on board customer concerns!

  21. Does anyone know if either the S685IP or M3 handsets can be made to require a PIN to be entered before answering a call? Or can this be done though Asterisk?

    The aim is to stop the kids answering business calls that will inevitably sometimes ring through on phones that they have physical access to.

  22. Ok cheers. Never mind. I was assuming Asterisk wouldn’t help as it’s already sent the incoming call to the phone, meaning entering a PIN on answering would have to be a local handset feature. But I’m very much an Asterisk noob, so it no doubt has lots of clever capabilities that I’ll need to learn.

    Love your blog by the way – what a goldmine of useful information!

  23. “Another thing the S68H can’t do: assign different ringtones to different incoming numbers.”
    I am using C470IP and I can assign different ringtones to different callers. You need to select “mark as VIP” in the phonebook and then you can change it.
    They are both Siemens Chagall platform and should have nearly identical functionality. Perhaps this has been added in a later firmware.

    The “PIN on answering” should work with asterix. Im am also a noob, but I guess it should do the following:
    – When business call comes in, do not pickup or transfer, but:
    – Dial the phone as a separate call and wait for pickup. You may even set the SIP name/phone number to match the outside caller.
    – Then ask for pin code. If correct, pickup the outside call and bridge the two calls.

  24. All ‘flaws’ you mentioned are all Siemens traditions.
    ( ” ‘mark as VIP’ in the phonebook” to differ ringtones is a long long tradition of Siemens.
    Another one is their ringtone melodies.)

    If you play with Siemens mobile phones long enough, you’ll find out the features were there long time ago. At that time, the features were very innovative.

    Frankly speaking, they are not a problem to me.
    I’m kind of missing the orange screens and the dull melodies.

  25. German are so stubborn.
    I don’t think they’ll change those after model S1000IP.

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