Please advise on which product to buy (line jack + do not disturb feature)

[BCDG]

Dear Forum Members:
 I would like to buy a OBitalk device to setup 1 to 3 cordless phones in my apartment.  Both phones can be the same phone number and it is not required that they act independent of each other.  I do not have land-line service in my apartment now.
 My first question is if I could benefit from the Line Jack of the OBi110 by using it to plug into a wall jack to provide a signal to other phones throughout the apartment.  I do not understand this feature very well nor do I understand my apartment wiring, except that I know previous tenants have setup a phone line with the local cable/phone company.  
 The second question is if I could prevent the phones from ringing at night with any or all of these products.  I saw that Google Voice has a do-not disturb feature, but it seems like I have to set it every night which I would find inconvenient.  Is there a way to automate this to, for example, only allow calls between 9am and 10pm?
 Thank you.

[jimates]

The line port is used to connect an incoming service, such as a landline, magic jack, nettalk etc. Only the Obi110 has this.

The phone port is the one you would connect to one of your existing phone jacks, which would provide service from the Obi to all jacks connected to that wiring. (Make sure there is no other active service on the wiring efore you connect the Obi to it). Instead of plugging your phone into the Obi, you plug it into the wiring and then plug your phone into the existing wiring.  All Obi devices have this of course.

The Obi has a do not disturb feature, but it must be activated using a star code every day also.

Google voice has custom ring schedules that you can set for each individual forwarding phone in your list. At your google voice phones list,
select "Edit" for the phone you wish to set a schedule for
select "show advanced settings" (this step not required for your Google Chat phone)
select "use custom schedule" for the ring schedule settings

You can set the multiple time ranges for weekdays and for weekends.

[BCDG]

Dear Jimates,
  THANK YOU for such a comprehensive answer.  I can see that any product will do and I can use a custom ring schedule to not have the phone ring in my apartment at unwanted times.  Perfect!  Thank you again, your amazing!