H04M3/22—Arrangements for supervision, monitoring or testing
H04M3/26—Arrangements for supervision, monitoring or testing with means for applying test signals or for measuring
H04M3/28—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor
H04M3/32—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor for lines between exchanges