LK2
LK6
LK7
LK5
LK3
LK4
LK1
Figure 5. Jumper locations on Model 2703 PC board.
The table below shows the factory default jumper settings. Following the table are descriptions for each jumper.
JUMPER SUMMARY TABLE
Jumper | Function | 75 ohm | 120 ohm | Factory Default |
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|
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LK1 | 75 Ohm TX Shield to GND | On | Off | On (connect) |
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|
|
|
|
LK2 | 75 Ohm RX Shield to GND | Opt.* | Off | Off (disconnect) |
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|
|
|
|
LK3 | Reserved |
|
| Off |
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|
|
|
|
LK4 | 120 Ohm Shield to GND | Off | Opt. | Off (disconnect) |
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|
|
|
|
LK5 | Configuration | On | Opt. | On (enabled) |
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|
|
|
|
LK6 | 75 Ohm Input Impedance | On | Off | } On (75 Ohm) |
LK7 | 75 Ohm Input Impedance | On | Off | |
|
|
|
|
|
*Opt. = optional setting, all others are required for proper operation
NOTE: one combination of jumper settings is required for 75 ohm operation, and another combination is required for 120 ohm operation. The Model 2703 is factory configured for 75 ohm operation.)
LK1: 75 Ohm Transmit Shield-to-Ground Connection
This setting determines whether the shield of the 75 Ohm (coax) transmit cable is connected to earth ground. This connection must be made when operating in 75 Ohm (unbalanced) mode. Conversely, this connection must not be made when operating in 120 Ohm (balanced) mode.
LK1 | Setting | |
Strap On | 75 | Ohm TX |
Strap Off | 75 | Ohm TX |
LK2: 75 Ohm Receive Shield-to-Ground Connection
This setting determines whether the shield of the 75 Ohm (coax) receive cable is connected to earth ground. This connection is optional when operating in 75 Ohm (unbalanced) mode. This connection must not be made when operating in 120 Ohm (balanced) mode.
LK2 | Setting | |
Strap On | 75 | Ohm RX |
Strap Off | 75 | Ohm RX |
LK3: DIP Switch S1-1 Enable
This strap is reserved for future use and must remain Off.
LK3 | Setting |
Strap On | Not a Valid Setting |
Strap Off | Normal Setting |
LK4: 120 Ohm Shield-to-Ground Connection
This setting determines whether the shield of the 120 Ohm (modular) cable is connected to earth ground. This connection is optional when operating in 120 Ohm (balanced) mode. This connection must not be made when operating in 75 Ohm (unbalanced) mode.
LK4 | Setting | |
Strap On | 75 | Ohm RX |
Strap Off | 75 | Ohm RX |
7 | 8 |
