Industrial Covert Unlimited is in its 20th year of operation. CU1.COM has been up since mid 1999. Great security & CCTV products and people who answer the phone!
Check this out!
ETS SMI-2 2 Channel Microphone Interface Adapter W/ 12VDC Input & Fast Cable Termination
The ETS SMI-2 powers 2 SM1 series microphones and distributes their audio outputs to RCA jacks (or 3.5mm) for connection to equipment with un-balanced line level inputs. This item is ideal for DVRs, remote monitoring applications, and multiple CCTV monitors (with built in speakers).
Features of the ETS SMI-2 microphone interface include simple 12VDC power input, easy cable termination, and circuitry protection via an auto reset type fuse.