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

**URL:** <https://forum.sierrawireless.com/t/in-mux-mode-hanging-up-a-voice-call-while-sending-sms-block/8910>\
**Category:** Legacy HL Series\
**Created:** [November 16, 2016, 10:59am UTC](https://forum.sierrawireless.com/t/in-mux-mode-hanging-up-a-voice-call-while-sending-sms-block/8910 "2016-11-16T10:59:31Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![hestia](https://avatars.discourse-cdn.com/v4/letter/h/6bbea6/32.png) [@hestia](https://forum.sierrawireless.com/u/hestia)\
**Post date:** [November 16, 2016, 10:59am UTC](https://forum.sierrawireless.com/t/in-mux-mode-hanging-up-a-voice-call-while-sending-sms-block/8910/1 "2016-11-16T10:59:31Z")

</div>

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:

```auto
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 :

```auto
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 :

```auto
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):

```auto
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

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<div class="post-metadata">

**Author:** ![Rex\_alex](https://avatars.discourse-cdn.com/v4/letter/r/73ab20/32.png) [@Rex\_alex](https://forum.sierrawireless.com/u/Rex_alex)\
**Post date:** [January 9, 2017, 10:13am UTC](https://forum.sierrawireless.com/t/in-mux-mode-hanging-up-a-voice-call-while-sending-sms-block/8910/2 "2017-01-09T10:13:07Z")

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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

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<div class="post-metadata">

**Author:** ![hestia](https://avatars.discourse-cdn.com/v4/letter/h/6bbea6/32.png) [@hestia](https://forum.sierrawireless.com/u/hestia)\
**Post date:** [October 10, 2018, 10:07am UTC](https://forum.sierrawireless.com/t/in-mux-mode-hanging-up-a-voice-call-while-sending-sms-block/8910/3 "2018-10-10T10:07:17Z")

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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