Telect MIX 56 user manual PERFORMING DIAGNOSTICS Running Loopbacks, 4-46, Alert

4 Software Operation MIX 56 User Manual

PERFORMING DIAGNOSTICS

Running Loopbacks

! ALERT

ALERT! When a loopback is running, the low-speed channel or high-speed circuit on which it is running is out of service.

The following loopbacks can be set from the Loopbacks screen:

Low Speed “Line”: The signal is sent through the DS1 LIU (Line Inter- face Unit) and looped back before reaching the Encoder/Decoder. The DS1 Received signal is looped back out as the DS1 Transmitted signal.

Low Speed “Local”: The demultiplexed DS1 signal from the M13 MUX is encoded and sent to the DS1 LIU Equalizer, where it is looped back through the DS1 LIU Decoder, and then multiplexed and added to the DS3 stream by the M13 MUX.

High Speed “Line DS3”: The received signal is sent through the DS3 LIU and through the M13 MUX Decoder, where it is looped back through the Encoder and put onto the DS3 stream. The DS3 Received signal is looped back out as the DS3 Transmitted signal.

High Speed “Local DS3”: The signal is sent through the DS1 LIUs, multi- plexed, and looped back before reaching the M13 MUX Encoder.

High Speed “Line, DS1 Ch xx in DS3”: The signal path is the same as the “Line, DS3” loopback, but instead of the entire DS3 signal being looped back, an individual DS1 channel of the Muxed DS3 signal is looped back.

The illustration below shows the path of each loopback.

DS3 LIU					M13 MUX				DS1 LIU
Noise		Clock &		DS3	DS2	Tributary	Tributary		Jitter	Pulse	Line
				Framer &	Framer &
Crosstalk	Equalizer	Data	Decoder					Encoder
				M32	M21	Mapper	Interface		Attenuator	Shaper	Driver
Filter		Recovery
				Demux	Demux
Line	Pulse			M23 Mux	M12 Mux	Tributary	Tributary		Clock &	Peak
			Encoder	& DS3	& DS2			Decoder	Date		Equalizer
Driver	Shaper					Mapper	Interface			Detector
				Framer	Framer				Recovery
	High-Speed Line								Low-Speed Local
			High-Speed Local						Low-Speed Line

MIX 56 Loopback Options

4-46 Telect, Inc. 122188-10 A0