Friday, June 4, 2010

Sending out SMS messages with SCOM

In order for SCOM to send out SMS messages a regular cellular phone needs to be attached to the RMS server. When this phone is being recognized by the server OS running on the RMS, SCOM is capable of sending out SMS messages.

However with this kind of setup there are some drawbacks to reckon with:

  1. A cellular phone is a bit clunky and prone to hard- and software errors. So changes are the cellular will fail sooner or later;
  2. A cellular phone attached to a server can invite certain administrators to use it for doing some private calls, so the RMS can no longer send out SMS messages;
  3. When a RMS fails and a MS is promoted to RMS, it takes time to reconnect the mobile device to the new RMS. Many times people forget it;
  4. A cellular phone requires software which is mostly written for desktops not for servers. Changes are likely new bugs are pumped into the server hosting the RMS role;
  5. A cellular phone is an overkill: one only needs SMS capability nothing more, nothing less;
  6. When the RMS is virtualized, how to go about connecting a cellular phone to that server?

So how to go about it? How to take care of these earlier mentioned drawbacks in such a way that one can send out SMS messages with SCOM and not being all to vulnerable? One can use internet solutions in order to send out SMS messages but that introduces new risks, many of which one can not influence at all. So another approach is required here.

The whole solution:
The solution is to be found in two pieces of hardware:

  1. a SIM box;
  2. a ‘translator’ of a serial connection over IP.

With the first mentioned solution one could do almost the trick and cover most earlier mentioned drawbacks. However, numbers 3 and 6 are still not covered for. Why? The SIM box needs to be directly attached to the RMS, using a serial connection. So when the RMS is virtualized, this cannot be done. Or when the RMS is physical and it fails, the new RMS (a promoted MS) cannot send out any SMS messages, only when the SIM box is attached to that server and the software is installed and properly configured.

In order to tackle number 3 and 6, the ‘translator’ comes into play. This solution connects on one site to the SIM box over a serial connection and translates it to an ordinary IP connection. When the software for this device is installed on the RMS it becomes ‘transparent’ and the RMS will be able to use the SIM Box as a modem using a ordinary LAN connection!

So the setup looks like this schematic drawing:


  • The RMS is connected to the LAN;
  • The Serial-Over-IP device (Digi One SP for instance) is connected to the LAN as well;
  • The SIM Box (Siemens TC35i for instance) is connected to the Serial-Over-IP Device through a serial connection;
  • On the RMS the software for the Serial-Over-IP Device is installed and configured (really easy);
  • On the RMS a Modem is added, the Siemens TC35i is being used here.

This way all the earlier mentioned drawbacks have been covered. On the MS the software for the Digi One is easily installed. So when that MS is promoted to RMS, the Notification Model using SMS is also easily transferred to that server.

Another huge advantage of the SIM Box is its robustness. It is not easily wrecked nor used by a systems engineer looking for a cheap way to make a phone call…

Where to get what:
- SIM Box, like the Siemens TC35i;
- Serial-Over-IP, like the Digi One SP.

Special Credits:
Without the help and advice of Alexandre Verkinderen this posting could not have been written. So all credits go to him.


Unknown said...

Thanks for that interesting post.
We'd like to set up a comparable setup but like to use our (old) Siemens M20 Terminal.

Do you know if this is going to work or have experience in other Siemens devices ?

Marnix Wolf said...

Hi Niclas.

Thanks for the nice words. Glad to hear this posting has been of any help to you.

I do not have any experience with the Siemens M20 Terminal. But why not try it? The worst thing which could happen is that it doesn't work and that your company has to purchase the Siemens TC35i which is very cheap.

Please keep me psoted about your experiences so I can update this blogposting, based on your experiences. Of course I will refer to you as the source.


Unknown said...

Hi Marnix,

you're welcome and thanks for replying.
I guess we will purchase that adapter mentioned in your setup and try the M20 to see what happens.

I will keep you informed if it worked. :)

Marnix Wolf said...

Thanks Niclas.

Unknown said...

Hi Marnix,

we just ordered the device and will configure everything so it works.
Will let you know if it works.



Marnix Wolf said...

Hi Niclas

Good to hear. Keep me posted.


Anonymous said...

Hi Marnix,

i have implemented sms-notification as described in your post. Thanks a lot, works very well.

One Question, is there no way to use more than 160 characters? This limitation is not clear to me because scom uses variables at this point.

best regards,

Marnix Wolf said...

Hi Andre.

the 160 character limit is a SMS limit and indeed, the variables can make a message way much longer than those 160.

The IT Crowd said...


After reading your article I thought I'd look into this too. I found a software version of the Serial to Ethernet device.

This works too.

Nice idea just I implemented this in software not hardware.


Hector Marcia said...

Hello Marnix,

Interesting info. We currently have a bulky (and expensive) device attached direct to the RMS to accomplish this task.

From the SCOM console perspective, how do you configure the Channel to forward SMS alerts using your setup?



Marnix Wolf said...

Hi Hector

You simply have to configure the SMS channel and all is well. A straight forward process it is.