Android creating SIP-GSM gateway

I need an application that runs on Android phones (4.0 or above) and can send/receive calls through SIP (Can use any sip stack like sipdroid) and forward it to the GSM network. The application should then forward the audio and convert from SIP to GSM and vice versa.

Full description below. Please review and message me with considerations. If any requirements are unable to be met, please let me know before we make a deal.


The goal of this project is to develop an Android application that can send calls through SIP and forward them to the GSM network AND receive calls from GSM and forward to SIP.

The application should then forward the audio and convert from VoIP to GSM and vice vers



The application working in APK format

Full source code

Simple manual for compiling and generating the application from source

A SIP client running on another phone that connects to the server via WIFI and able to demonstrate the functionality in this project.


- Route call from SIP to GSM

- Route call from GSM to SIP (preconfigured SIP client)

- Convert audio from/to SIP and GSM networks

- Able to run on Android 4.0 and up.

Application Configurations

- Enable or disable the app

- Enable to receive calls only on wifi or all networks

- Enable to route calls from GSM to SIP (SIP address is configured through an API)

- The number to send the call should be configured through an API that is supplied with the APP

- Enable to route calls from SIP to GSM

- Must run on background

- Must be very lightweight to run on small memory devices

- Configure SIP Accounts.

Sip Requirements

- Register on Sip Proxy/Gateway

- Receive call authenticated by IP, user/pass or no authentication.

- Make calls with or without authentication

- Forward DTMF digits using RFC2833 or inband

- Use codec G711 and GSM

- Be able to use codec G729

- Receive through GSM one 1 simultaneous call and rout it to a predefined SIP client

- Be able to store a CSV with all calls made

Skills required:

Android, VoIP

An standard SIP client running on a seperate android phone will have to connect to the SIP server that was developed on the other android phone via wifi and an incoming and outgoing call would have to to be demonstrated.

Skills: Android, Mobile App Development, Java, Asterisk PBX, VoIP

See more: android forward calls to sip, vodroid, asterisk on android, sip gsm software, android phone as gsm gateway, chan_mobile, asterisk gsm gateway, freepbx gsm gateway, affordable sip gsm gateway, best sip gsm gateway, sip gsm gateway linux, sip gsm gateway usb, sip gsm gateway software, android sip gsm gateway, sip gsm gateway usb modem, android trunk sip gsm, sip gsm gateway asterisk, phone sip gsm gateway android, android trunk sip gsm gateway, android app sip gsm gateway

About the Employer:
( 0 reviews ) Aachen, Germany

Project ID: #20302900

15 freelancers are bidding on average $648 for this job


Hello, I read your description and got what to do. I am looking forward to discussing more for your project. I am ready now, please message me to start your project. I have 7+ years of experience in this field I am More

$500 USD in 7 days
(56 Reviews)

Hello Sir / Madam, We will be happy to work for an application that runs on Android phones (4.0 or above) and can send/receive calls through SIP. Let us chat to clarify everything. Please check our work portfolio: h More

$750 USD in 21 days
(105 Reviews)

Hi, its pretty simple for me but I have few questions to ask, knock me for further discussion, PLEASE DON'T AWARD PROJECT BEFORE DISCUSSION. Thank You

$666 USD in 7 days
(43 Reviews)

We are top softphone client development team. we can customize your requirement using linphone. Do you have sip server? we dealt with top companies of telecom. What are the features you are looking for Calling, Messag More

$500 USD in 7 days
(10 Reviews)

Dear Sir,⭐⭐⭐⭐⭐ I have carefully read your project description and felt very interesting. I have strong expertise and high-level skills in iOS & Android mobile app development. And I have a strong background with J More

$600 USD in 10 days
(12 Reviews)

Hello Project Manager **Immediate Start** No Upfront Payment. Payment After Delivery I am expert with 7+ years of experience in creating & designing App & Website Android , Ios Application , shopify/eCommerce websi More

$1150 USD in 22 days
(17 Reviews)

Hi there, Hope you are doing well. I have read your requirements about your project very deeply and I believe that I can complete your project within your budget and time. A, Desired website and application [ IOS and More

$500 USD in 7 days
(6 Reviews)

Hello, How are you? I hope you are fine. I have saw your descriptions what you want. I would like to work for your project if you want. I have over 5 years of experiences on the development of website&android&ios. I a More

$300 USD in 3 days
(2 Reviews)

Hi there, I have checked the details. I have rich experience with Android, Asterisk PBX, Java, Mobile App Development, VoIP. Please initiate the chat so we can discuss this job in detail. I am new to bu More

$555 USD in 9 days
(1 Review)

Hello, Greetings for the day!!! I am an expert Mobile Apps Developer. I have gone through your project details and analysis the work. As per your job you are looking for android app developer who can work on your pro More

$500 USD in 20 days
(1 Review)

Hi, Hope you are doing well! I would like to work on your project. I have excellent in skills with more than 6 Years experience. I'm sure that I will complete with high quality in the shortest time. I am always availab More

$900 USD in 7 days
(0 Reviews)

Hello! I can build your application as you mentioned in project description. I am an independent and professional developer holding 100% completion rate. I am highly interested about your project, Please knock me for a More

$250 USD in 8 days
(8 Reviews)

Hi, Thanks for posting !!! I have 14 years of experience in Website and Mobile apps. I have checked the requirement and understand. I have created App SIMILAR to Android creating SIP-GSM gateway do you want More

$300 USD in 3 days
(0 Reviews)

Hello, We have developed various VoIP apps from scratch which follows SIP protocol. We are also a Platinum certified partner of 3CX in US and we can also develop other VoIP apps from scratch. We are also well versed More

$750 USD in 20 days
(0 Reviews)

Using an Android phone as a GSM VoIP Gateway! Our solution App realizes the dream that builds VoIP Gateway into an Android phone. It makes your Android phone upgrade to movable VoIP Gateway immediately. You can not o More

$1500 USD in 21 days
(0 Reviews)