No data conection after switching from HL8548 to HL7692 (M2M)

IoT Modules Legacy HL Series
1

Hello all,

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???

Kind regards
Marcus

2

Hi Marcus,

Please check if v.2.27 can solve this issue or not.
You can download the FW v2.27 here:
https://source.sierrawireless.com/resources/airprime/software/hl7692-firmware/

3

Hi Sierra_klin1 and all the other people out there!

Thank you for your advice.

Updating to FW 2.27 did not solve the issue: :confused:

+++ ATH <--> ATH OK
AT+CFUN=1,1 <--> AT+CFUN=1,1 OK +PBREADY +SIM: 1 +KSUP: 0
ATE0&D2+KSLEEP=2;+CBST=71,0,1 <--> OK
AT+COPS=2 <--> OK
AT+WMANTSEL=1;+COPS=0 <--> OK
AT+CGDCONT=1,"IP","o#####b.##" <--> OK
AT+WPPP=1,1,"##UNAME##","##PWORD##" <--> OK
AT+CREG? <--> +CREG: 0,5 OK
AT+CSQ <--> +CSQ: 10,99 OK
AT+COPS? <--> +COPS: 0,0,"Vodafone.de",0 OK
AT+CCID? <--> +CCID: 898################# OK
AT+KCELL? <--> +KCELL: 7,
                       0, 8, 63,62f220,297,454f,20,255,
                       1,10, 35,62f220,297,d049,16,
                       1,29,255,62f220,ffff,ffff,0,
                       1, 2,255,62f220,ffff,ffff,0,
                       1,33,255,62f220,ffff,ffff,0,
                       1,41,255,62f220,ffff,ffff,0,
                       1,45,255,62f220,ffff,ffff,0
                       +KCELL: 0 OK
ATD*99***1# <--> CONNECT
~.}#.!}!}!} }4}!}$}%.}"}&} } } } }%}&..)}4!2~ <--> ~.}#.!}!}!} }4}"}&} } } } }%}&R}8}0D}'}"}(}"n.~~.}#.!}"}!} }4}!}$}%.}"}&} } } } }%}&..)}4.[~

Normally - using al HL8548 - the username and password-exchange would / should follow and then a welcome-message should be received. Instead - using the HL7692 - the C023-Packages continue infinitely.

Via USB one can observe:

at+cgdcont? <--> +CGDCONT: 1,"IP","o#####b.##","##2.##1.#1#.##6",0,0,0,0,0,0 OK
at+cgatt? <--> +CGATT: 1 OK
at+cgact? <--> +CGACT: 1,1 OK

Now, to make thinks more difficult (as they obviously are at this point), let’s repeat this with a
non-existing APN:

AT+CGDCONT=1,"IP","jstimagineanapn.non" <--> OK
AT+WPPP=1,1,"anyfunnyusername","a_random_secret" <--> OK
ATD*99***1# <--> CONNECT
~.}#.!}!}!} }4}!}$}%.}"}&} } } } }%}&[.0}4..~  <--> ~.}#.!}!}!} }4}"}&} } } } }%}&R}8}0D}'}"}(}"n.~~.}#.!}"}!} }4}!}$}%.}"}&} } }} }%}&[.0}4}/.~

Any further idea(s) or suggestion(s)?
500 HL8548 boards running fine without Problems in 2G/3G and 500 HL7692 modules waiting for joining
their PCBs - but not before running fine in the dev-kit and test-circuits.

Kind regards and a merry Xmas!
Marcus

4

Hi Marcus,

For HL7692, if the uname and pword are mandatory for the APN “o#####b.##”", you should not use AT+WPPP=1,1,"##UNAME##","##PWORD##", because +WPPP does not work for the external PPP dial up app (ATD99**1#).

Please input the uname and pword in the external PPP dial up app.

You can try first with the windows ppp dial up as well.

I test with Windows PPP dial up app and Linux ppp-2.4.7, it works well when set PAP auth.

5

Hello Sierra_klin1 and the other readers!

after some more traces I found a (perhaps THE) difference between the HL8548 and the 7692:

Establishing a connection, on the 8458 the application says “hey, we could do PAP or CHAP” and receives
the answer “PAP accepable” / “CHAP acceptable”. Afterwards it continiues with the highest possible procedure as the reply says.

26,OUT *** FF03C021 * 01010014 * 010405D4 * 020600000000              * 0506F7165E06 * 35CF 
31,IN  *** FF03C021 * 01010019            * 020600000000 * 0305C22305 * 050652181044 * 0702 * 0802 * CFA5                                           
14,OUT *** FF03C021 * 04010008                                                       * 0702 * 0802 * F844                        
26,IN  *** FF03C021 * 02010014 * 010405D4 * 020600000000              * 0506F7165E06 * DEA6 
27,IN  *** FF03C021 * 01020015            * 020600000000 * 0305C22305 * 050652181044 * 02A1 
27,OUT *** FF03C021 * 02020015            * 020600000000 * 0305C22305 * 050652181044 * B6F8 
26,OUT *** FF03C021 * 01010014 * 010405D4 * 020600000000              * 050652181044 * 24AE 
27,IN  *** FF03C223 * 0101001510913F58C149608E12686DA08E27FB8F01B1 
32,OUT *** FF03C223 * 0201001A104ADB03729AF389750FF96AB48CD2065E41444D494ED66D

On the 7692 this answer (which should contain the common standards for both sides) is empty.

31,OUT *** FF03C0 * 2101010019 * 010405D4 * 020600000000 * 0305C22305 * 05067C653514 * B017                                         
26,IN  *** FF03C0 * 2101010014            * 020600000000              * 050652181044 * 0702 * 0802 * 6EE1 
14,OUT *** FF03C0 * 2104010008                                                       * 0702 * 0802 * F844                         
14,IN  *** FF03C0 * 2103010008 * 0304C023 * 2248                        
22,IN  *** FF03C0 * 2101020010            * 020600000000              * 050652181044 * AC71        
22,OUT *** FF03C0 * 2102020010            * 020600000000              * 050652181044 * 8DEB         
22,IN  *** FF03C0 * 2101020010            * 020600000000              * 050652181044 * AC71         
22,OUT *** FF03C0 * 2102020010            * 020600000000              * 050652181044 * 8DEB        
26,OUT *** FF03C0 * 2101010014 * 010405D4 * 020600000000              * 050652181044 * 24AE 
16,IN  *** FF03C0 * 210301000A                                        * 05068602DA91 * C0CB                     
22,IN  *** FF03C0 * 2101020010            * 020600000000              * 050652181044 * AC71         
22,OUT *** FF03C0 * 2102020010            * 020600000000              * 050652181044 * 8DEB         
22,IN  *** FF03C0 * 2101020010            * 020600000000              * 050652181044 * AC71         
22,OUT *** FF03C0 * 2102020010            * 020600000000              * 050652181044 * 8DEB

This is a non-valid state for the application, which restarts with “hey, we could do PAP or CHAP”.
So here we’ve got the reason for the infinite loop without passing AUTH.

Perhaps this empty answer means “do whatever you want, all would be fine” - or something else.

Having to change the app software would be a major task (e.g. certification) so it would be the easiest
way to have some init-parameters to be passed to the HL7692 to beheave in the “good old 8548-way”.

Kind regards
Marcus

6

Hi Marcus,
For HL7692, I suggest check first the PAP or CHAP supported with the following

AT+CGATT=0
AT+CGDCONT=1,“IP”,“xxxxx”
AT+WPPP=1,1,“AAAAA”," BBBBB" //PAP
AT+CGACT=1
AT+CGACT=0

AT+CGATT=0
AT+CGDCONT=1,“IP”,“xxxx”
AT+WPPP=2,1,“AAAAA”,“BBBBB” //CHAP
AT+CGACT=1
AT+CGACT=0

From your HL8548 log, PPP succeeds with CHAP (C223) AUTH.

Note that for HL7/HL8, the PAP/CHAP/User/Pass is managed by app software.
Please check app software about the PAP/CHAP/Username/Password settings, e.g. search the API like:
pppSetAuth(PPPAUTHTYPE_ANY,“AAAAA”,“BBBBB”);
pppSetAuth(PPPAUTHTYPE_CHAP, “AAAAA”, “BBBBB”);
pppSetAuth(PPPAUTHTYPE_PAP,“AAAAA”,“BBBBB”);