Here's some technical info for you. Hope this helps.
CONTACT CLOSURE ADJUNCT
-- Maximum of two contact closure device may be connected to one PARTNER ACS Communications System using the Contact Closure Adjunct (PEC: 60625).
-- A one-touch Contact Closure feature button(s) must be programmed on one, several or all PARTNER ACS System Telephones. This is the feature button that is used to control the Contact Closure device, e.g., a door opening strike-plate.
-- The customer’s electrician must supply the Contact Closure device such as a door strike-plate, contact-closure operated relay (electric motor, external signage, etc.) or a 48-volt doorbell transformer (external alert).
-- The PARTNER ACS Contact Closure Adjunct must be installed within 150 feet from the PARTNER ACS Control Unit if two contact closure devices are used or within 800 feet if only one contact closure device is used.
-- The Contact Closure Adjunct cannot be installed out-of-doors.
-- The customer’s electrician is responsible for making the wire connection (electrical wire, not phone wire) from the PARTNER ACS Contact Closure Adjunct to the contact closure device, e.g., door opening strike-plate, doorbell transformer, etc.
-- Maximum contact closure device voltages and current are:
• 30 VAC, 1 Amp
• 50 VDC, 1 Amp
-- The contact closure output from the Contact Closure Adjunct is electrically “dry”. In other words, the contact closure device that the customer’s electrician provides must provide all voltage and power.