JK Audio THAT-2<div style="text-align: left;"><strong>[Product Information]</strong><ul><li><span class="a-list-item"> Works with analog， digital， PBX， and ISDN telephones RCA and XLR line in and out Switch selects between carbon， dynamic or electrethandset types No battery or AC adapter needed Durable diecast aluminum construction </span></li><li><span class="a-list-item"> Line Inputs: RCA， 20 k ohms， 250 mV RMS (+12 dBmmaximum) XLR female， 20 k ohms， 250 mV RMS (+12 dBm maximum) Line Outputs: RCA， 600 ohms， 100 mV RMS (-16 dBm nominal.) XLR male， 600 ohms， 100 mV RMS (-16 dBm nominal.) Handset Interface biased for Electret， Dynamic， and Carbon handsets. </span></li></ul></div><img src="http://ecx.images-amazon.com/images/I/41HTqFf5OfL.jpg" noproxy>