XRT5794ES View Datasheet(PDF) - Exar Corporation
Part Name
Description
MFG CO.
'XRT5794ES' PDF : 11 Pages View PDF
XRT5794ES
Switch Position
1
IC Pin
28
2
27
3
(Not Used)
4
19
5
18
6
10
7
9
8
8
Symbol
LPMOD3
LPMOD4
Switch Setting
Off
On
Off
On
Function
Channel 3 Remote Loop Back Mode
Selected
Channel 3 Local Loop Back Mode
Selected
Channel 4 Remote Loop Back Mode
Selected
Channel 4 Remote Loop Back Mode
Selected
LPEN3
LPEN4
MONEN
TXEN3
TXEN4
Off
Channel 3 Loop Mode Enabled
On
Channel 3 Normal Operation
Off
Channel 4 Loop Made Enabled
On
Channel 4 Normal Operation
Off
Monitor Output Enabled
On
Monitor Output High Impedance
Off
Transmitter 3 Output Enabled
On
Transmitter 3 Output High Impedance
Off
Transmitter 4 Output Enabled
On
Transmitter 4 Output High Impedance
Table 5. Dip Switch S3 Functions
HARDWARE CONFIGURATION CHANGES
This section describes hardware changes necessary for
different modes of operation. It assumes that the demo
board is initially configured for 120W balanced E1 service.
75W Unbalanced E1 Operation
Replace the 3-circuit audio type jacks used on the
line-side inputs and outputs with BNC connectors (9
total). Wire the center pin of each BNC connector to the
adjacent circuit borad pad labeled “75”.
With the demo board oriented so that the power
connections are in the upper left hand corner, reposition
the nine clip-on jumpers so that they now connect the top
two pins on the 3-pin headers labeled E1 through E9.
Balanced or unbalanced cable operation is chosen by a
clip-on jumper for each channel and by the installation the
appropriate types of input and output connectors. T1/E1
rate selection is done by one DIP switch section.
100/120W impedance selection for balanced operation
involoves a resistor change.
100W Balanced T1 Operation
Replace 120W resistor R2, R4, R6 and R8, with 100W
parts.
Replace 68W resistors R10, R12, R14, R16 and R18, with
62W parts.
Rev. 2.00
9
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