How Trigger Interval Settings affect image transmission in Ltl Acorn 2G Cellular Cameras

Fig 1: 6210 Wireless PCB and SIM900 Modem

This post is an explanation of how the interval time setting in the cameras menu affects the transmission of image data over a 2G cellular network.

This does not apply to the 6310 cameras with 3G modems when working over a 3G network, which were introduced at the end of 2016.

Acorn cellular cameras use the SIM900 GPRS 2G modem which can connect with either the GSM or the GPRS service. It is a class B device which means it can only use one or the other at a given time. During GSM service ( voice call, SMS and MMS ) the GPRS service is suspended, and then resumed automatically after the GSM service has concluded. 

Acorn cellular cameras utilise the SIM900 wireless modem to provide GSM ( SMS and MMS ) and GPRS ( internet access for sending an image in an email using SMTP ) functionality. 

In Acorn cellular cameras the SIM900 prioritises the GSM service when programmed by the user to periodically listen for SMS remote control messages. The SIM900 also prioritises the GSM service in response to a trigger