SMPTE LTC audio interconnections can be balanced, unbalanced or a combination of both. Audio equipment varies considerably in this area. There are four common connector types that you are likely to encounter, RCA, 1/4" pin Tip/Sleeve phone plug (1/4P-T/S),
1/4" pin Tip/Ring/Sleeve phone plug (1/4P-T/R/S), and 3-pin XLR. The wiring lists below show the most common configurations for the various output/input interconnections.
ETC products provide a 3-pin female XLR connector for SMPTE.
For balanced operation, connect source directly to input
For Unbalanced input, connect pins 1 and 2 together in the user XLR 3-pin male plug, and connect "Signal" to pin 3.
ETC Unbalanced input cable end