The MT8733 includes two telephone ports that support standard (landline) telephones and other devices. The MT8733 is designed to work with Comcast Xfinity voice service only.
To use the telephone ports, first, make sure you have subscribed to Xfinity voice service. This service may be provisioned to support either one phone line on Tel1 or two phone lines on both Tel1 and Tel2, with two different phone numbers.
You can connect almost any standard telephone equipment to an MT8733 telephone port. This includes almost anything that connects using an RJ11 phone plug—telephones, cordless phone base stations, answering machines, etc. (If you want to connect a security system, check with the security system manufacturer for compatibility).
You can connect individual devices, or you can connect multiple devices that plug into the same phone line. (Their Ringer Equivalence Numbers need to add up to 5 or less.) One way to connect multiple devices is to plug the MT8733 phone port into a jack connected to existing telephone wiring. Before doing this, make sure to disconnect the wiring totally from the telephone company’s network demarc. This is normally done by unplugging a phone cord at the jack nearest to where the phone line comes into your home. After you unplug that phone cord, check that none of the phones on that line gets dial tone when you go off-hook. If they don’t get dial tone, it’s safe to connect a phone cord from one of the line’s jacks to an MT8733 phone jack. After you do that and power up the MT8733, all the phones on that line should get dial tone.
You may want to attach a cordless phone base station to the MT8733, and then place cordless handsets wherever you like. The Battery Purchase or Replacement section describes how you can make sure you have phone service even if your MT8733 loses power.
Telephone Lights
Here is a table describing the behavior of the Tel1 and Tel2 Lights:
The lights blink slowly during active calls and are OFF if no service is provisioned. The lights are solid for each line when voice service is provisioned and ready.
Note that the Tel2 port will only function if you have two phone line services from Comcast Xfinity.
Making and Receiving Calls
You can make and receive calls through connected telephone equipment just as you would with any other landline telephone service. Remember to dial 1 before long-distance calls within the United States. Check with Xfinity whether your plan supports international dialing, and for dialing instructions.
There are many services that come with Xfinity voice, including CallerID, Call Waiting, and others, depending on your plan. Please see the Xfinity voice page for details.
https://www.xfinity.com/support/articles/phone-quick-reference-guide
Operating on Battery Power after Power Loss
When an optional Motorola-supplied battery backup system is installed, your MT8733 will automatically failover to battery power if there is a power outage at your location. The battery will support standby operation for Tel1 for up to eight hours and talk time of up to five hours. This can be increased to up to twenty-four hours of standby operation, and talk time of up to fifteen hours with the addition of extra batteries. Note that attached phones such as cordless phones that require their own power will require their own backup power source. Standard corded handsets do not require their own backup power source.
When running under battery backup power, only the Tel1 and Battery lights remain lit. The battery light behaves according to this table:
The Battery Purchase or Replacement section on page 19 describes how you can make sure you have phone service even if your MT8733 loses power.