I am looking to use a HB-702 and HS-6 Telephone handset as 4wire speaker position on an Eclipse matrix I am told I can use the EB7-4W daughter card to change the HB-702 from a Partyline unit to a 4wire unit
1) Do you need one of these modules for each of the 2channels on the unit?Answer: According to the manual 1x EB7- 4W modulewill provide you with 2 separate 4wires, therefore each unit will use 2 portson the Eclipse matrixEB7-4W pdf manual

2) If you use this, do you still need a PS-702 or can theunit be powered from mains if used in this way?Answer: the customer needs to purchase a PSU unit from Clear-Com orbuy a suitable PSU locallyThe unit requires 20-30VDC @ 500mAA suitable DC source is the Clear-Com 400067Z 30V 500mA AC-DC converter.