Vodafone Dialing Issues 24/07/15

!!Please note this has been resolved by Vodafone (31/07/15).  We would recommend testing your alarm however!!

Last week we were notified by an installer that he was unable to get the dialer to dial mobile numbers using a Vodafone SIM; texting was unaffected.  We replaced the SIM card in the unit for an EE based reseller (Vectone) and the dialer functioned perfectly.

After investigating the cause, we found Vodafone have started to mis-report the call status of an out-bound call (more information below).  The simple resolution is to use an O2 or EE based SIM provider.  We updated the firmware to allow Vodafone to be used, as is, but with some additional commands required:

divert en

With Diverts Enabled the call length is now set by (without divert en it defaults to 5s):

ctime xx.  (the default is 58 seconds)

If you are using a Vodafone SIM in your dialer, run an alarm test to see if your local cell is affected by the issue.  If it is, ensure you have SMS alerts (textnum xxxxxxxx.) set up along with calling alerts.  You will require firmware F3.15 or later for ‘divert enable’ to be effective.

The Issue

To understand the issue we need to look at the information we obtain about the call from the network using the AT+CLCC command.  This command reports back the call status.  Here is an example of how a call is handled using the Vectone EE network SIM:

..+CLCC: 1,0,2,0,0,”07930666555″,129,””….OK..
..+CLCC: 1,0,2,0,0,”07930666555″,129,””….OK..
..+CLCC: 1,0,2,0,0,”07930666555″,129,””….OK..
..+CLCC: 1,0,2,0,0,”07930666555″,129,””….OK..
..+CLCC: 1,0,2,0,0,”07930666555″,129,””….OK..
..+CLCC: 1,0,2,0,0,”07930666555″,129,””….OK..
..+CLCC: 1,0,3,0,0,”07930666555″,129,””….OK..
..+CLCC: 1,0,3,0,0,”07930666555″,129,””….OK..
..+CLCC: 1,0,3,0,0,”07930666555″,129,””….OK..
..+CLCC: 1,0,3,0,0,”07930666555″,129,””….OK..
..+CLCC: 1,0,0,0,0,”07930666555″,129,””….OK..
..+CLCC: 1,0,0,0,0,”07930666555″,129,””….OK..
..+CLCC: 1,0,0,0,0,”07930666555″,129,””….OK..
..NO CARRIER….
OK..

The CLCC data is checked every second.  When the dialer is triggered we see the status of the call goes to status 2 (highlighted in red) which is the ‘DIALING’ phase.  This is the time when the call is set up with the network.  After 6 seconds we see the next CLCC report shows the call is now at status 3 ‘ALERTING’ indicating the remote phone is ringing – at this stage the recipient can hear the phone ringing.  When the phone is answered, we see the call goes to status 0; the ‘ACTIVE’ state.  This means the phone has been answered.

Finally, after 3 seconds the call is ended by the recipient and we see ‘NO CARRIER’ is sent by the network.  This is an example of how a call should be handled.

..+CLCC: 1,0,2,0,0,”07830666575″,129,””….OK..
..+CLCC: 1,0,2,0,0,”07830666575″,129,””….OK..
..+CLCC: 1,0,2,0,0,”07830666575″,129,””….OK..
..+CLCC: 1,0,2,0,0,”07830666575″,129,””….OK..
..+CLCC: 1,0,2,0,0,”07830666575″,129,””….OK..
..+CLCC: 1,0,0,0,0,”07830666575″,129,””….OK…
.OK..
..OK..
..+CLCC: 1,0,2,0,0,”01517283167″,129,””….OK..

Above shows how Vodafone have been reporting a Mobile Originated (MO) call since the issue arose.  As before we see the call immediately going to status 2 after a dial command as expected.  However, prior to when the recipient’s phone starts to ring the status of the call is reported at status 0.  When a call goes from status 2 to 0, this is indicative of a call going to voicemail.  Voicemail does not ring out and it is diverted without the ringing phase hence the dialer moves on to the next number as we can see.

This can occur normally with Vodafone as they play a voice message telling the caller to top up credit when credit is low.  However, this behaviour has started to happen on all calls no matter what credit is available and causing the dialer to skip all calls.

The command ‘divert enable’ allows calls to go to a diverted number.  Normally you would not want this as there is no point calling voicemail with the dialer.  However, as there is no accurate way of detecting the status of a call with this Vodafone issue ‘divert enable’ will allow the call to continue.  This command was originally intended for our intercoms to allow mis-resporting (it occasionally happened with some MVNOs like Lyca Mobile) but must be used on an affected Vodafone SIM.

As the length of an alarm dialer call is limited to 5s this is insufficient time for a mobile call to be set up.  Therefore, the firmware we released this week (29/07/15 F3.15) allows the CTIME command to set the length of the call when diverts are enabled.

CTIME xx.

Hopefully this network issue will be resolved shortly by Vodafone.  If this persists and Vodafone is the only available network, we recommend returning the dialer to Advent Controls for a firmware upgrade.  Our latest firmware release allows any future updates to be performed over the internet using GPRS.

Dialer Information Page

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