The Electronic Warfare rules in StratOps: AAR (pages 98-101) layout several modes of operation for ECM Suites and Active Probes:
ECM Suites can either generate an ECM field, or an ECCM field.
Active Probes can generate ECCM fields in either Short or Medium range mode.
The rules for both ECM Suites and Active Probes individually state a unit may only operate one at a time.
The Watchdog system is found on page 90 of TacOps: AUE, only has the ECM Suite language above, but otherwise "works in the same way as the Clans’ standard ECM and Light Active Probes" [emphasis mine].
Question: Does the Watchdog employ one ECM Suite mode AND one Active Probe mode, or must it pick ONE mode out of the four?
This is relevant because installing two pieces of gear allows one Probe and one Suite to operate at the same time.
Follow up question: If an ECM Suite is operating in ECCM mode, does that effect stack with an Active Probe's ECCM field? Beyond possibly reducing Large Craft ECM by -3 per affected hex, this could potentially allow a single Fighter or Small Craft to negate a second Large Craft ECM field (ECM systems on such craft are limited to affecting a single Large Craft field on page 100 of StratOps, but Active Probes seem to have no such limit on the previous page).