3G Xbee taking 30 seconds to associate, is this normal?

Question

Hi,

I'm using an XBC-M5-UT-001 Cellular XBee with a Vodafone UK SIM card and everything seems to be working but it's taking a really long time to connect.

When I take the module out of sleep mode I get the 00 status message (Hardware reset or power up) straight away, and then about 30 seconds later I get the 02 message (Registered with cellular network). Is this normal? it's consuming a huge amount of power keeping the module on long enough to send a single tiny data packet.

Thanks,

Ben.

Answer 1

We do not support any type of "connected sleep" on XBee Cellular 3G (I actually don't think that 3G networks support any power-saving modes like this to begin with).

When the XBee Cellular module goes to sleep (such as by using the SLEEP_RQ pin with ATSM=1), we completely power off the cellular modem, and on the subsequent wakeup we power the modem back on, but this will be effectively the same as power-cycling the XBee entirely, or using airplane mode.

Also, based on your note that you are getting a 00 modem status frame, it sounds like you are completely shutting the XBee off, not using pin/cyclic sleep. The 00 modem status frame indicates a complete restart of the XBee processor. In this case, each time you power the XBee on, the modem will also be completely power-cycled, hence the ~30 seconds needed to associate.

If you want power-saving mode with quick re-association time, you will need to wait until we release XBee Cellular LTE-M with support for PSM mode.

Comments

Ok, thank you!