Yes, actually you don't want the Magicjack service, because it will put tones on the line.
Standard phone lines have DC, which the telecom engineers call "talk battery", supplied through a series impedance from the phone company equipment. When you connect a modem to a modem, there is no source of “talk battery.”Some modems require the "talk battery" and some can operate without it. The modem inside the ReplayTV does not require “talk battery.” Modems with a telephone line interface using a transformer and relay typically do not require “talk battery,” Modems with an electronic interface, such as those in PCMCIA cards and many internal modems for desk and laptop computers, do, because the electronic interface depends on the “talk battery” for power. When you connect two modems back to back, there is no source of "talk battery."
Under "Make sure your modem is compatible with your Replay", paragraph 8, one method of providing "talk battery" is to connect a 9 volt battery in series with a 330 to 1000 ohm resistor. You would obtain a T adaptor like the one in the picture and a phone jack. (Most T adaptors have the plug molded into the plastic, instead of the short cord shown in the picture. That is fine.) Connect one modem to one jack of the T adaptor, the other modem to the other jack, and insert the plug into the phone jack. Connect the 9 volt battery in series with the resistor to the red and green wires of the phone jack for testing.
The battery will get depleted fairly quickly. The suggestion is to plug the T adaptor into a Magicjack or Chatcord as a source of talk battery. You would not sign up for the phone service and, hopefully, the Magicjack or Chatcord would then not put tones on the line. However, I suggest completing the procedure with a battery and obtaining a phone simulator, also known as a telephone line emulator, for the long term.
A suitable line emulator is the Viking DLE-200B, which is available on ebay and has been found to work well. It will provide “talk battery.” Once you receive your line emulator, test it using two telephones plugged into the jacks, using one telephone to call the other. Make sure that the second phone rings, the line is quiet and conversation can take place. Repeat the “Make sure your modem is compatible with your ReplayTV” section, but wait for the text RING before typing ATA.
(Some ebay sellers have the DLE-200B without its AC adaptor. If you can obtain the AC adaptor from a separate source or improvise your own AC source, this can be a good buy.)
In the virtual machine, you will need to edit mgetty. Log on as root, password root, type the command line“edit pkg/sbin/mgetty”, change the line PHONESIM=n to PHONESIM=y and the change the line beginning with DELAY2 to DELAY2=600. Save the file (Alt-s). Reboot the virtual machine (command line “reboot”).
Why use a line emulator? If your PC modem has a relay, you may find the clicks annoying and the relay may eventually wear out. However, more importantly, you will likely have frequent failures. The modem tries to answer every 30 seconds or so. If the ReplayTV attempts connect after the modem has already answered, the modem may not finish synchronizing and sending the connect message before the virtual machine sends it a message to disconnect. The call will be lost, a message is left on your ReplayTV and the schedule update is delayed until the next day.
Note that the fastest modems typically connect at 33,600 bps in the back to back arrangement, even if they are called 56K modems. The modems used by internet service providers send at rates exceeding 33,600 but, while consumer modems receive at the higher rates, they are typically limited to a send rate of 33,600.