AT+CHLD giving only error

[dhanraj_kmr]

Hi All,
I am trying an application where i want to attend more than one call, put one call on hold and attend another call etc.
From the AT command spec i understand that AT+CHLD is the command which does that.

I am using SIM900. I am connecting modem to my laptop.

1. I called the number which is in the modem from one number.
2. Attend the call using ATA command
3. And called the same no from another mobile
4. Now i am able to get second call
5. Now when i send AT+CHLD=2<CR><LF> it just giving "Error"

AT+CHLD=0,1,2,3,4 nothing works.
From the spec
"Note These supplementary services are only applicable to tele service 11 (Speech: Telephony)."
I am not getting the point here.

Is it possible to achieve what i am trying to do here?

 

[mathespbe]

Tele service 11 is used only for telephony purpose....

 

[dhanraj_kmr]

What do you mean by "telephony purpose"?

I have connected a speaker to the modem so i want to attend different calls and answer them using mic which i connected. Everything is working fine but the hold option is not working.

Or is there any modem which i can buy and use it solve this issue?
I am running out of time. Fast response is highly appreciated.

 

[jayanth.devarayanadurga]

See if modem is in text mode.

 

[dhanraj_kmr]

Text is only for SMS. Isn't it?
Can you brief me how it is affected my action?

However i will try to swich between Text mode and PDU mode.