Cisco phones:

You can set a call forward via your Cisco phone by pressing the Settings button and head to the Call Forward option. You’ll then have a few options, a forward for all numbers, a forward for is your number is busy and an option for a forward for no answer. On any of these options you can press the edit button and enter your number you would like to forward to here and then press Save.

Alternatively, you can set a call forward by going into the web configuration utility for your Cisco and then heading to Voice > User and then enter your number(s) under the Call Forward section of the page. Make sure that ‘Cfwd Setting’ is set to ‘Yes’.

Yealink:

To enable call forward in phone mode:

• Tap the Menu icon, > Call Features > Call Forward or press the transfer button when the phone is idle.
• Tap the desired forwarding type
• Depending on your selection:

If you tap Always Forward:

• Tap the On radio box of the Always Forward field.
• Enter the destination number you want to forward all incoming calls to in Call Forward To field.
• (Optional.) Enter the always forward on code or off code respectively in the On Code or Off Code field.

If you tap Busy Forward:

• Tap the On radio box of the Busy Forward field.
• Enter the destination number you want to forward incoming calls to when the phone is busy in the Forward To field.
• (Optional.) Enter the busy forward on code or off code respectively in the On Code or Off Code field.

If you tap No Answer Forward:

• Tap the On radio box of the No Answer Forward field.
• Enter the destination number you want to forward unanswered incoming calls to in the Forward To field.
• Tap the grey box of the After Ring Time field.
• Tap the desired ring time to wait before forwarding from the pull-down list. The default ring time is 12 seconds.

Alternatively, you can set a call forward by going into the web configuration utility for your Yealink and then heading to Features > Forward&DND. Here, change the phone mode to Custom and you would enter your forwarding number in the ‘Target’ field for 'Always Forward', 'Busy Forward' and 'No Answer Forward’. Be sure to change the setting to ‘On’ for each forward you have a number entered for.

Having the Mode set to Phone will set the call forwarding settings to be applicable for that particular account on the Yealink, whereas setting it to Custom will automatically configure that call forwarding number for all accounts of that Yealink phone.

Grandstream

You can set a call forward via your Grandstream phone by pressing Menu > Phone > Call Features > Choose Sip Account > Forward All. From here, you would enter the number you would like all calls to be forwarded to.

This is also true with softphones as seen below!:

In Bria, you set the call forward option by going into your SIP Account settings > Voicemail > Forwarding > Forward to…

Underneath you’ll also see a ‘forward when busy’ field and check box, which in essence is ‘forward when busy’ option you’ll see in other devices and softphones.