The number of wires necessary for this connexion is dependant on whether you are using twowire or fourwire voice path - if a twowire voice path, then a total of four wires are required (two voice plus E and M); if a fourwire voice path is used, then a total of six wires are used (four voice plus E and M).
The E and M leads are necessary for fault supervision of each voice channel.
Don't forget to set SQU and TRM values correctly.