will it work on 220v ?

Enrique - The VTech VG104 requires 100-120V AC power. Thank you for your interest!

Can I listen remotely to messages when away from home?

Hi - Yes, you can access messages recorded on the answering machine of the VTech VG104 remotely. 1. Dial your telephone number from any touch-tone telephone. 2. When the system plays your announcement, enter the two-digit security code (check the manual for the remote access code). 3. The answering system will play new messages (if there is any), then followed by old messages. Hope this helps!

can the ringer in phone and base be turned off and the phone still be used if another phone in the house rings?

Ken - Yes, the VTech VG101 has a ringer volume setting on the cordless handset that can be set to off. Also, the telephone system can still be used to make and receive landline calls even if the ringer volume is set to off. Thank you for your interest!

Need four phones? Do I buy two of this model?

Lisa - You can install two sets of VTech VG101-21 in the same line. They will work as extension phones, but features are not shared. If you need 4 cordless handsets, you may check the model IS8151-4. Thank you!