I failed migrating from a HL8548 to a HL7692 for a M2M-project and need some advices to get things running.
Situation: I’m operating a HL8548 with a small MCU-controlled application over UART, communicating via a
private APN and a roaming-allowed SIM (mostly using Vodafone 2G/3G network) The microcontroller sets
the correct Context via +CGDCONT and then the connection is established by ATD99**1#. After the CONNECT
the MCU starts a PAP-AUTH and after success begins with the transmission of data.
Now, after changing to a HL7692 (and only adjusting the init-string by adding +KSLEEP=2 to avoid communication problems caused by sleepmode) the module still can register in the network (GSM+EGPRS & LTE), but gets stuck in
the PAP-AUTH (same code on the MCU side, only init-string changed).
Comparing the AT-Command-Guides I can’t find any difference in needed (additional / different) configuration for
the HL7692 but obviously there must be a different behaviour as things won’t run (switching back to the HL8548 everything is perfect just after a restart - again for to the HL7692 and the mess is back again).
Used init-string for the HL8548: ATE0&D2+CBST=71,0,1 and with the additional +KSLEEP=2 for the HL7692.
With both modules, network-registration runs without problems: +CREG: 0,5 … +COPS: 0,0,“Vodafone.de”,7 (or 2 or 0, depending on module & preferred AcT), the PDP Context is defined (+CGDCONT=1,“IP”,“myAPN”) , data-call is initiated and after CONNECT the behaviour gets different:
HL8548: PAP-Auth starts, several 0xC023-Telegrams, username / password, and the “welcome”-message appears.
HL7692: PAP-Auth starts, auth can’t be completed, ending in an endless-loop. (GSM+LTE)
Setting the APN to a non-existing one results in the exact same behaviour (though the module gets protocols in PAP-style from the network - also with a fake-APN).
Providing login-data for the correct APN via +WPPP (while configuring for PAP) seems not to help anything on the HL7692.
Any hints, suggestions or stupid mistakes made but not seen???