T1/E1 Mini-Octal™ Isolation Modules HALO Electronics T1 / E1 Mini-Octal™ Isolation Modules are SMD 8-Channel Quad Port T1 / E1 transformers UL/EN60950/DEMKO recognized. These isolation modules feature an extended temperature range of -40°C to 84°C and patented open frame construction. The T1 / E1 modules offer 1500VRMS and are RoHS compliant.