Cordless phones can not 'forward' a call to an outside line.
Forwarding must be controlled by the ATT, Verizon, or landline provider.
Please contact your provider to determine if you have call forwarding feature built into your service package.
Then, follow the instructions of your landline phone provider.
Here is the instructions for Verizon:
Activating Call Forwarding
You can activate Call Forwarding whenever you want your calls to be sent to another phone, including a mobile phone. Once activated, all your calls will be sent to the forwarding number you request. Each time a call is forwarded, you will hear one short reminder tone on your home phone, but you will not be able to answer the call from your home number.
- Lift your telephone's receiver and listen for a dial tone.
- Press .
In some areas you must use
Dial 1172 on rotary or pulse-dialing phones.
- When you hear the tone, set or change the Call Forwarding number by dialing the telephone number where you want your calls transferred.
You will hear the number you entered ring. When the number is answered, Call Forwarding is activated.
- If the call is not answered or the line is busy, hang up and call the number again within two minutes.
You will hear two short tones telling you that Call Forwarding is activated.
- Hang up the receiver.