Hello again,
To have a second working modem, you would have to take out a second subscription (activation of a new line), an additional connection fee of 25.35, with a DSL Start subscription at 0 + a abonnement Swisscom TV at 19 or 29 (if you wish have the recording function or not), which makes a total of 44.35 or 54.35. Knowing that you must contact an electrician to find out if you need to install a second line between the connection box of your home and your accommodation, which generates additional costs.
Hoping to have been useful to you, I wish you a pleasant day.
Lorenzo