Do you subscribe to Spectrum telephone service over your cable connection? If so, your phone wiring connects to the telephone jacks built into your EMTA gateway unit. Wiring the home phone jacks to your cable gateway usually doesn't change the use of your cordlesss phone handset, but don't expect to have a total of 8 phones connected to your cable service; I think their limit is five.
You do need to have a phone jack within about ten feet of the gateway unit location. There are two line connections so that a fax machine or an alarm system can preemt [interrupt and override] any call in progress on your regular telephone wiring. Your cable installer and alarm company can work together to take it from there.