Custom field / type text. Need to add default value from another field.

[ke-gordon]

I want to be able to autofill a custom field with the value that is in the Type field if I don't enter a value manually. The custom field would be added to the device model. So as an example if a device has a Type of 3750g-12s I would like the custom field to auto fill with 3750g-12s. Does anyone know if this is possible? I know there is a default field in the custom field config but I don't have a clue how to use it and cannot find any good documentation on it.