From ISP perspective, sending notifications for different events like expiry alerts, quota warning alerts, service disruption alert, welcome messages, password recovery via sms, etc etc to users is generally a good idea and becoming essential part of services. To send SMS in a proper way, its recommended get 3rd party SMS gateway services so that SMS goes by your company name and there should be no legal issue. but for smaller networks with lesser number of users, hiring 3rd party services is not financially suitable.
For a smaller network you can simply add any GSM Modem (example huawei or Teltonika) and use any local mobile operator SIM to send / receive SMS from your billing system because in our country SMS packages are dirt cheap. Ufone provides 100,000 SMS package in just 8$ per year, other operator’s packages are also cheap. You can install KANNEL sms gateway in your linux system and use it to send SMS in automated way using your billing or any other customized method. BUT the issue is if you send bulk SMS in single go, there are strong chances that your SIM may get blocked by the operator because there are some official and un official restrictions imposed by either Operator or Telecom authorities like some sources states that
SIM gets blocked If you cross 200 SMS limit in 15 minutes and some mobile operator blocks SIM if you send 500 sms in 1 hour.Ref: http://www.web.pk/2014/pta-devised-a-policy-to-stop-bulk-sms/
[Suitable for SOHO]
If you are using KANNEL, and sending SMS using BASH scripts, add delay by using “sleep 20” (20 seconds delay) in the loop section so that there should be at least 10 or 20 seconds delay in between each sms sending. After adding 20 seconds delay to the code, only 3 SMS will go out per minute. You can adjust and fine tune this delay as per your requirements.
OR if you are using Radius Manager , then edit its sms gateway API php file and add the sleep delay as showed in the image below …
Now try to send Bulk SMS using RM ACP Panel, and you will see the delay in logs as well. : )~
In KANNEL there is an option ‘throughput‘ via which per sms sending can be controlled but for somehow it didn’t worked for ever. Therefore I used delay codes in the scripts or at the processing of submitting code.
I posted this issue at various forums but yet couldn’t found any solution on howto to add DELAY for outgoing sms in KANNEL configuration. If any one knows the working solution. Kindly do let me know 🙂
Also share your experiences on how your SIM got blocked, what are other operators SMS sending limits? PTA limits etc.
Some Reference URLS for KANNEL