HL7800 waking up modes


We are using HL7800 in our application today and I am trying to understand if its possible to wake up/reach/ping the module from a mobile cellular command when the module is in some kind of sleep/power saving mode?

If yes, what does this require from the telco operator; Static IP? any special setup? what about roaming, is it possible while roaming?

Hi @janvidar,
Yes, it is possible to wake up/reach/ping the module from a mobile cellular. You need to verify something:

  • Network supports PSM (Power Saving Mode)/ eDRX (extended DRX)
  • The mobile can wake up module by using SMS or IP reception.
  • The module should be assigned a public IP in case it is set as TCP/UDP server or the other devices want to ping/reach to
  • It works fine in roaming

Please see attached document for configuration
AT command:
AirPrime - HL7800 - Low Power Modes Application Note:
Let feel free share any concern you have. Help us tick Solution if your question is answered

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Hello Vianney,

Our network provider supports PSM yes, but I do not understand how you can reach the HL7800 module in a PSM state using SMS or IP reception. At which chapter in the manual describes this best?


So first thing to state is that assuming your are in coverage then the unit can wake up and send data at any point.

With regards receiving downlink connectivity and trying to keep it as simple as possible.

  • Sleep - Unit is on the network, not employing any techniques to specifically turn the radio off.
  • eDRX - Unit is on the network and it will listen to incoming paging requests up to every 80 seconds (theoretically longer but not in practice), so there will be a maximum latency of 80 seconds between trying to connect and getting a response from the unit.
  • PSM - So the unit is in power save mode, when it is in PSM it has an IP address assigned to it and can go to sleep for minutes/hours/days (depending on network setup), the network typically determines when it needs to ping into the network and this is typically around every 4 hours which is the only time you would be able to send it a message (obviously not good for IP based messaging.

The above is a really simple explanation of the modes, there is a lot more detail and it does not touch on the IP set up.