Copssh is an OpenSSH server and client implementation for Windows systems with an administration GUI.
It was previously available for free. Now the previous versions are free but for new version you have to pay for the new functionality & support.
Here is a small guide to install CopSSH & configure it to use for the Unity Connection or CallManager.
Installation of CopSSH.

Accept License agreement

Specify an installation location

Specify a service account.

Installation will start.

The installation is done..
Change in the string PasswordAuthentication in the file sshd_config (C:\Program Files\ICW\etc) to PasswordAuthentication yes .
Configuration for call Manager & unity Connection.
you must have one local user with admin rights or domain user with admin rights to change the path in call manager/unity connection backup device option.
you have to activate that user in CopSSH to use the sftp server
Go to Start --> All Programs --> Copssh --> Activate a user .

Choose desired user

Choose the passkey & the user is activated.
Add the device in the call manager or unity connection & it is ready for backup.