Problems with NowSMS using 2 modems

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Paul Crick
New member
Username: Paulcrick

Post Number: 7
Registered: 07-2011
Posted on Tuesday, September 18, 2012 - 07:47 pm:   

We started out with NowSMS Lite using a single Option ICON 322 modem and had great success for the most part.

We migrated to an installation of the full version of NowSMS, using two of the same modems. Testing each one worked fine in the lab, but once we put the system in production the modems would regularly crash out and become unresponsive. A search of the forums found another customer with the same issue (see for details). Apparently it's a driver issue - the driver wasn't written to support multiple modems (understandable - mostly these are "one stick, one laptop" right?)

We swapped one of the modems out for a Nokia CS-12 and while it all looked promising to begin with but then started exhibiting the similar issues with either or both modems becoming unresponsive.

Modem wise I can choose from an Option ICON 322, a Nokia CS-12, a Nokia CS-17, or an AT&T USBConnect Mercury modem - which I believe is a Sierra Wireless 885 or fairly close to it.

In an ideal world we'd connect to the carriers via SMPP or HTTP instead of using MM1/MM7 but it's not feasible or cost effective for us at this time.

Can you offer any pointers on using multiple modems to send/receive both SMS and MMS? Is there a simple "gotcha" that I'm missing, or are chances of success generally slim when using multiple modems in this fashion?

Thanks in advance
Bryce Norwood - NowSMS Support
Board Administrator
Username: Bryce

Post Number: 8023
Registered: 10-2002
Posted on Wednesday, September 19, 2012 - 09:07 pm:   

Hi Paul,

Sometimes you can resolve these issues by making sure the modems are plugged into different USB hubs on the computer, as the problems are power related.

Most USB modems draw 500 mA, which is the max power draw per port supported in the USB version 2 standard.

A typical PC should have no problem supplying 500 mA to multiple USB ports simultaneously.

But we have seen some issues where problems like you describe can go away by moving the modems to different ports. Typically a PC has multiple USB controllers with different ports connected to different controllers (for example, front and back side ports).

I wish I had some better suggestions. One other thread is asking about GSM modem pool products on Ebay. I've been hesitant to try them, but maybe I need to go back to my colleagues and see about ordering one to test ... manufacturer info is just too unclear.

I do have one setting that might be worth trying.

Edit SMSGW.INI, and under the [SMSGW] header, add:


This setting controls some behaviour regarding regarding how NowSMS talks to the modem. I remember an incident where a particular USB stick was locking up requiring a reboot, and this setting mysteriously made a difference. It is worth a try.