In mux mode, Hanging up a voice call while sending SMS block

IoT Modules Legacy HL Series
1

Hello,
I’m using HIloNCV2 in mux mode with 3 channels constantly opened:

  • CHANNEL 0 for signal strength checking : periodic AT+CSQ sending and +CSQ checking
  • CHANNEL 1 for SMS sending in text mode : sending AT+CMGS="+33XXXXXXX", waiting for “>”, sending the message and +CMGS checking
  • CHANNEL 2 for voice call (just ringing) : sending ATD+33XXXXXXX, waiting and checking for *PSCSC return values and hanging up after *PSCSC: 1, 4, sending AT+CHUP

When I only send SMS it works fine:

SEND[1]: AT+CMGS="+33XXXXXXX"
RECV[1]: > 
SEND[1]: Message body
RECV[1]: +CMGS: 205
RECV[1]: OK

When I only do a phone call, it works fine as well :

SEND[2]: ATD+33XXXXXXX;
RECV[2]: *PSCSC: 1, 0,, "+33XXXXXXX", 145, 0,,,
RECV[2]: OK
RECV[2]: *PSCSC: 1, 3,,,,,,,
RECV[2]: *PSCSC: 1, 4,,,,,,,
SEND[0]: AT+CSQ
RECV[0]: +CSQ: 18,0
RECV[0]: OK
SEND[2]: ATH

If I do both at the same time, it almost always work :

SEND[1]: AT+CMGS="+33XXXXXXX"
RECV[1]: > 
SEND[1]: Message body
SEND[2]: ATD+33XXXXXXX;
RECV[2]: *PSCSC: 1, 0,, "+33XXXXXXX", 145, 0,,,
RECV[2]: OK
RECV[2]: *PSCSC: 1, 3,,,,,,,
SEND[0]: AT+CSQ
RECV[0]: +CSQ: 23,7
RECV[0]: OK
RECV[2]: *PSCSC: 1, 4,,,,,,,
SEND[2]: ATH0
RECV[2]: *PSCSC: 1, 21,,,,,,,
RECV[2]: OK
SEND[0]: AT+CSQ
RECV[0]: +CSQ: 18,7
RECV[0]: OK
RECV[1]: +CMGS: 1
RECV[1]: OK

[b]EXCEPT IF I “hang up” the phone call JUST AT THE TIME I send the SMS. In that case, the Hilo seems to block (no more AT command response on any CHANNEL):

SEND[1]: AT+CMGS="+33XXXXXXX"
SEND[2]: ATD+33XXXXXXX;
RECV[1]: > 
SEND[1]: Message body
RECV[2]: *PSCSC: 1, 0,, "+33XXXXXXX", 145, 0,,,
RECV[2]: OK
SEND[0]: AT+CSQ
RECV[0]: +CSQ: 18,5
RECV[0]: OK
RECV[2]: *PSCSC: 1, 3,,,,,,,
RECV[2]: *PSCSC: 1, 4,,,,,,,
RECV[1]: +CMGS: 213
RECV[1]: OK
[b]SEND[1]: AT+CMGS="+33XXXXXXX"
RECV[1]: > 
SEND[1]: Message body[/b]
SEND[0]: AT+CSQ
RECV[0]: +CSQ: 18,0
RECV[0]: OK
[b]SEND[2]: ATH[/b]
RECV[2]: *PSCSC: 1, 21,,,,,,,
 RECV[2]: OK
ATD+33XXXXXXX;
RECV[2]: *PSCSC: 1, 0,, "+33XXXXXXX", 145, 0,,,
RECV[2]: OK
RECV[2]: *PSCSC: 1, 3,,,,,,,
RECV[2]: *PSCSC: 1, 4,,,,,,,
SEND[0]: AT+CSQ
[b]SEND[2]: ATH
Timeout CHANNEL 1
Timeout CHANNEL 2
SEND[2]: ATD+33XXXXXXX;
SEND[0]: AT+CSQ
Timeout CHANNEL 0
SEND[0]: AT+CSQ
Timeout CHANNEL 0
SEND[0]: AT+CSQ
Timeout CHANNEL 0
SEND[1]: AT+CMGS="+33XXXXXXX"
SEND[0]: AT+CSQ
Timeout CHANNEL 0
Timeout CHANNEL 1
Timeout CHANNEL 2
SEND[2]: ATH 
Timeout CHANNEL 2[/b]

For hanging up, I tried AT command ATH0, ATH4, AT+CHUP but all of them create the same problem.
I want just to stop phone call on CHANNEL 2 (which it does) and let CHANNEL 1 send the SMS and CHANNEL 0 continue checking signal strenght…
Is it possible to send a SMS and do a phone call at the same time using mux OR is there a bug somewhere?

I hope someone could help me.

Best regards,
Thomas Spitz

2

Hi,
What is the status of AT+CGSMS?
You can change the service for SMS messages from circuit switched to packet switched for both GPRS and SMS work together.

-Alex

3

Hi Rex_alex,
At the present I do not use GPRS at all.
Here the answer of AT+CGSMS?

send[0]:AT+CGSMS?#015
RECV[0]:+CGSMS: 1
RECV[0]:OK

Thanks for your reply