In mux mode, Hanging up a voice call stops GPRS connection

IoT Modules Legacy HL Series
1

Hello,

On a HiloNcV2 / HL6528RD, I use 4 virtual links via gsmMuxd.

On the virtual link of index 2, I make a phone call and on the virtual link index 3, I keep an active GPRS connection.

My problem is that I can not stop the phone call without breaking the GPRS link although the command AT + CHUP should allow it according to the documentation. Also mentionned in this post : [Hilo] What is the different between ATH[type] and AT+CHUP?

Here below a trace with AT+CHUP:

send[0]:AT*PSNTRG?#015
RECV[0]:*PSNTRG: 5,1,“208”,“01”,“6901”,“2A9B”,“Orange F”,1,0,0
RECV[0]:OK
send[0]:AT+CSQ#015
RECV[0]:+CSQ: 21,99
RECV[0]:OK
send[2]:ATD+33622222222;#015
RECV[2]:*PSCSC: 1, 21,
RECV[0]:*PSCSC: 1, 0, “+33622222222”, 145, 1,
send[0]:AT+CSQ#015
RECV[2]:OK
RECV[2]:PSCSC: 1, 0, “+33622222222”, 145, 1,
RECV[0]:OK
send[0]:ATPSNTRG?#015
RECV[0]:*PSNTRG: 5,1,“208”,“01”,“6901”,“2A9B”,“Orange F”,1,0,0
RECV[0]:OK
RECV[0]:*PSCSC: 1, 3,
RECV[2]:*PSCSC: 1, 3,
RECV[0]:*PSCSC: 1, 4,
RECV[2]:*PSCSC: 1, 4,
send[2]:AT+CHUP#015
pppd[801]:, rcvd [LCP TermReq id=0x3]
pppd[801]:, LCP terminated by peer
pppd[801]:, Connect time 1.2 minutes.
pppd[801]:, Sent 0 bytes, received 0 bytes.
RECV[0]:*PSCSC: 1, 21,
pppd[801]:, Script /etc/ppp/ip-down started (pid 812)
pppd[801]:, sent [LCP TermAck id=0x3]
pppd[801]:, Script /etc/ppp/ip-down finished (pid 812), status = 0x0

I tried other commands like ATH0, ATH4 but this one returns a CME 3 error. These commands do not cut the GPRS connection but neither the current phone call.

Here below a trace with ATH0 instead of AT+CHUP:

RECV[0]:*PSNTRG: 5,1,“208”,“01”,“6901”,“2A9B”,“Orange F”,1,0,0
RECV[0]:OK
RECV[1]:+CMGS: 221
RECV[1]:OK
send[2]:ATD+33622222222;#015RECV[2]:OK
RECV[2]:*PSCSC: 1, 0, “+33622222222”, 145, 1,
RECV[0]:*PSCSC: 1, 0, “+33622222222”, 145, 1,
2RECV[0]:*PSCSC: 1, 3,
RECV[2]:*PSCSC: 1, 3,
RECV[0]:*PSCSC: 1, 4,
send[0]:AT+CSQ#015
RECV[2]:PSCSC: 1, 4,
RECV[0]:+CSQ: 2,4
RECV[0]:OK
send[0]:ATPSNTRG?#015
RECV[0]:*PSNTRG: 5,1,“208”,“01”,“6901”,“2A9B”,“Orange F”,1,0,0
RECV[0]:OK
send[2]:ATH0#015
RECV[2]:+CME ERROR: 3

Hope you could help

2

Yes you are right. After AT+CHUP, both MUX Voice call and PPP connection are disconnected. But if remote side disconnect the voice call , then the PPP will be kept online.

3

Hello Sierra_klin2,

If I understand correctly, this means that the post [Hilo] What is the different between ATH[type] and AT+CHUP? is not correct regarding CHUP

If AT+CHUP doesn’t manage to hang up a voice call without stoping GPRS connection, which AT command should I use to stop the voice call without stopping the GPRS connection?

As HL / Hilo are class 10 modems, there should be a way to do so, am I wrong?

Best regards,
Thomas

4

For HL6RD, It seems no good solution for this.
I did not verify it but maybe you can try the following:

  • MUX init
  • MUX#1: PPP(ATD*99#)
  • +++ to suspend the PPP connection
  • MUX#2: ATD12345678;
  • AT+CHUP
5

Hello Sierra_klin2,
What you suggest cannot work in my situation because after dialling a GPRS connection with ATD*99# the mux channel is taken by the pppd deamon that create the Internet link. Thus it is impossible to send any AT command on this mux anymore as it is already busy with ppd. FYI, I all the same tried but it doesn’t work.
I also tried to send +++ on MUX(2) but it just timedout and CHUP still close the GPRS connection.
So what is the solution to make HL hang up a phone call while keeping GPRS connection active?
Thanks in advance
Thomas

6

FYI, AT+CHUP works as mentionned in [Hilo] What is the different between ATH[type] and AT+CHUP? for Hilo.

It only doesn’t work for HL but it is even worse than what you wrote:

With HL6528RD, I tried to hang up the voice call from the receiver phone and it also disconnect the ppp. Have you tried on your side?

It sounds like a bug in HL. I’m using HL6528 SIERRA HL6N,008.10