Patton electronic 2701/D, 2701/B, 2701/C user manual SW1-8 Enable/Disable Loop Tests from DTE

SW1-8: Enable/Disable Loop Tests from DTE

Use Switch SW1-8 to allow Model 2701 to enter loopback tests when the DTE raises the appropriate loop request pin.

	S1-8				Setting
	Off			Response to DTE Loopback Request Enabled
	On			Response to DTE Loopback Request Disabled
Position				Function	Factory Default	Selected Option
SW2-1				Line Coding	Off	HDB3
SW2-2		CRC-4 multiframe			Off	Disabled
SW2-3			Data Inversion		Off	Data Not Inverted
SW2-4			V.54/CSU select		Off	V.54 RDL loop
SW2-5				FPS enabled	Off	Enabled
SW2-6			V.54 Response		On	Disabled
SW2-7				Not Used	N/A	N/A
SW2-8				Not Used	N/A	N/A

Switch SW2-1 Line Coding: HDB3 (default)

Use Switch SW2-1 to control the Network Line Coding options. Set these options to be the same as the Line Coding given to you by your Service Provider. If you are using two Model 2701s together as short range modems, set both units to HDB3.

SW2-1	Line Encoding
Off	HDB3
On	AMI

Options: HDB3, AMI

HDB3 In this line coding, the transmitter substitutes a deliberate bipo- lar violation when excessive zeros in the data stream are detected. The receiver recognizes these special violations and decodes them as zeros. This method enables the network to meet minimum pulse density requirements. Unless AMI is required in your application, HDB3 should be used whenever possible.

AMI Alternate Mark Inversion defines a pulse as a “mark,” a binary one, as opposed to a zero. In an E1 network connection, signals are transmitted as a sequence of ones and zeros. Ones are sent as pulses, and zeros are sent as spaces, i.e., no pulse.

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