Manual

Issue 2, December 2018 Model 391 User Guide
Page 4 Studio Technologies, Inc.
Revision History
Issue 2, December 2018:
1. Documents new feature which allows simultaneous call detection on channels 1 and 2.
2. Documents expanded frequency detection range for call signals. (Was 20 kHz, now
18-23 kHz nominal.)
Issue 1, May 2018:
1. Initial release.