Sim900 airtel sim problem

[rmrps]

Hi Friends i am using sim900 module to send and receive message if i am inserting airtel h2 type simcard when sending sms it sends some extra Junk Characters if i am inserting airtel normal old simcard and all other simcard it was working fine no extra characters i am giving the example of junk characters below

ID:12014 M/S:GRI
D DROP.üðððððððð
ðððððððððððððððð
ðððððððððððððððð
ðððð..+CMGS: 6..
..OK..

the normal perfect Output is

ID:12014 M/S:GRI
D DROP...+CMGS:
6....OK..

Please give me your guidance to resolve this issue

 

[ashu840]

connect your modem with adaptor and simultaneously with the microcontroller, leave it ON and try after some time.

 

[rmrps]

connect your modem with adaptor and simultaneously with the microcontroller, leave it ON and try after some time.

Thanks for the reply i am tried but the extra characters coming only sending sms and startup of module when registering to the network and if any incoming calls ariving

 

[Mrunal Ahirrao]

check your power supply voltage is it dropping? or regular?