Two question: 1. Can I accept collect calls with cox? 2. Do I need to use the EMTA or can I use VoIP adapters?

1. Most of the time yes. Sometimes there are blocks, and maybe a moderator here can check, but 99% of the time the issue causing the collect call not to go through is your girlfriend's number isn't in the list of contacts the person telephone list. Another way to test it is to just collect call her from your cell phone. If you can get through, any problem on Cox's end is null.

"The inmate must complete and sign a Offender Telephone List – Inmate Phone Policy “Indiana Code – 11-8-2-5(a)(8), identifying no more than 20 names and the telephone numbers of who could be called." See similar code for your correctional facility. 

2. Your modem will only have phone jacks if you pay for phone service from Cox. If you have a Oola or Vonage adapter, or other, then it should work fine as long as your network is configured for it. Usually a good idea to go modem > router > adapter so your router can manage the bandwidth use of the VOIP system. For more specifics I would need to know what equipment you're using. But as far as data is concerned, data is data; VOIP, HTTP, streaming video, etc. 

I should probably clarify that Cox Digital Telephone is not VOIP but rather a packet switched phone service.  While it is data driven it does not use the Internet therefore it'll be required to use one of our eMTA's.  There is no rental charge for the eMTA since it is a requirement for the service to work so long as you have active phone service with us.