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Chapter 5

Pod Configuration

5.1 Changing the Pod Configuration
5.2 V.35 Pod Configuration
5.2.1 Frame Ground
5.2.2 Transmit and Receive Data
5.2.3 Request to Send/Clear to Send
5.2.4 Data Terminal Ready, Data Set Ready, and Carrier Detect
5.2.5 Ring Indicate
5.2.6 Clock Options Transmit Clock Pins 69

Receive Clock 70

External Clock Pins 71

5.1 Changing the Pod Configuration

The V.35 Configurable Pod allows you to configure the V.35 connectors to match the equipment to which you intend to connect. Configuration jumpers for each individual port are inside the pod. Instead of building special cables, simply configure each port to use your existing cables or to use "straight-through" cables. Pods come factory strapped to appear as DTE devices. You may set the pod up to appear as a DCE device or various non-standard configurations by changing the jumper settings. To change the pod configuration, see the following diagram.

  1. Disconnect the pod from the pod cable.

    

  2. Unscrew the four (4) screws closest to the edge on top of the pod.
    

    

  3. Separate the halves of the pod.
    

    

  4. Flip the pod top upside-down to expose the configuration jumpers. There are three sets of jumpers, one set for each port.
    

    

  5. Use needle nose pliers or tweezers to grasp the jumper you wish to move, pull the jumper up and off, then move it to the desired location.
    

    

  6. After setting jumpers for all ports, reassemble the pod box and reconnect the pod cable.
    

    









5.2	 V.35 Pod Configuration





The V.35 Configurable Pod provides a breakout box-like capability. Each port on the pod is configurable to suit the device connected to it by setting jumpers located inside (See Section  5.1, Changing the Pod Configuration, for details). The factory default sets up the TX 2000/TX 3000 board as a DTE device. The DCE configuration on the right is a suggested setting to make the TX 2000/TX 3000 board appear as a DCE device.


Note:  Some remote connections use pin 24 (External Clock) in a nonstandard way. If the TX 2000/TX 3000 board is acting as the DCE providing clock and cannot send or receive data, try adding jumpers to the external clock as shown by the arrows in the following diagram:







5.2.1	 Frame Ground





Frame ground provides a shield to protect against unwanted radio frequency emissions from the cables and pod. Frame ground is NOT connected to signal ground. Frame ground connects through the pod cable back to the frame of the computer and is also connected to the aluminum case of the pod. Typically, Frame Ground is attached to the DTE equipment. To do this, use Position 1 and do not attach Frame Ground at the DCE device. If attached at both ends, a problem can arise with ground loops. If the device attached to the pod provides Frame Ground on pin A, set this jumper to Position 2 to prevent ground loops.





Figure 8.	 Frame Ground






5.2.2	 Transmit and Receive Data





The Transmit Data outputs from the TX 2000/TX 3000 board are connected to pins P & S while the Receive Data inputs to the TX 2000/TX 3000 board are connected to pins R & T when the jumpers are in Position 1 (standard DTE operation). If the device you are attaching requires TX 2000/TX 3000 board Transmit Data on pins R & T (the remote device's receive data pins) and expects the TX board to receive data on pins P & S (TX 2000/TX 3000 board acts as the DCE device), use Position 2. A loopback setting, Position 3, allows the Transmit Data to be looped back to the Receive Data on the TX 2000/TX 3000 board and the Transmit Data to be looped back to the Receive Data on the V.35 connector. The loopback setting can be used for test purposes.





Figure 9.	 Transmit and Receive Data






5.2.3	 Request to Send/Clear to Send





The Request To Send output from the TX 2000/TX 3000 board and Clear To Send Input to the TX 2000/TX 3000 board are connected to pins C and D, respectively, when the jumpers are in Position 1 (standard DTE operation). If the device you are attaching requires Request To Send on pin D and Clear To Send on pin C (TX 2000/TX 3000 board acts as the DCE device), use Position 2. A loopback setting, Position 3, allows Request To Send to be looped back to the Clear To Send on the TX 2000/TX 3000 board and the Request To Send to be looped back to the Clear To Send on the V.35 connector.





Figure 10.	 Request to Send/Clear to Send






5.2.4	 Data Terminal Ready, Data Set Ready, and Carrier Detect





The Data Terminal Ready output from the TX 2000/TX 3000 board is connected to pin H and the Data Set Ready and Carrier Detect inputs to the
TX 2000/TX 3000 board are connected to pins E and F, respectively, when the jumpers are in Position 1 (standard DTE operation). If the device you are attaching provides Data Terminal Ready on pin F and requires Data Set Ready and Carrier Detect as inputs on pins E and F, use Position 2 (TX 2000/TX 3000 board acts as the DCE device). A loopback setting, Position 3, allows Data Terminal Ready to be looped back to Data Set Ready on the TX 2000/TX 3000 board and the Data Terminal Ready to be looped back to the Data Set Ready and Carrier Detect pins on the V.35 connector.





Figure 11.	 Data Terminal Ready/Data Set Ready/Carrier Detect






5.2.5	 Ring Indicate





The Ring Indicate input to the TX 2000/TX 3000 board is connected to pin J when the jumper is in Position 1. If you wish to ignore Ring Indicate, use Position 2.





Figure 12.	 Ring Indicate






5.2.6	 Clock Options





Data clocks are the timing signals used for synchronous communications. Applications require a wide variety of clocking configurations. The configurable pod allows great flexibility in this area. The clock option jumpers allow the three sets of clock pins X/AA, V/Y, and U/W on the V.35 connectors to be connected to any of the three TX 2000/TX 3000 board clock signals (note that V.35 uses balanced signals and hence 2 pins for each of the clock signals). Note the distinction between the pins which are the connection points on the V.35 port connectors, and the signals, which are the connections to the TX 2000/TX 3000 board.



The TX 2000/TX 3000 board has three clock signals per port: 





 Clock Signal



 Description




 Transmit Clock 



 Input to the TX 2000/TX 3000 board. Used to allow another device (such as a modem) to clock a TX 2000/TX 3000 board serial port transmitter. Transmit data will be synchronized with this clock. Must also be software selected.




 Receive Clock 



 Input to the TX 2000/TX 3000 board. Used to allow another device (such as a modem) to clock a TX 2000/TX 3000 board serial port receiver. Receive data must be synchronized with this clock. Must also be software selected.




 External Clock 



 Output from the TX 2000/TX 3000 board. Used to allow the TX 2000/TX 3000 board to provide clocking to another device (such as a modem). The frequency of this clock is software programmable
















.Each V.35 port connector has three clock pins. The following sections correspond to these pins. By setting the jumpers, any clock signal can be connected to any clock pin.


 Transmit Clock Pins





Figure 13.	 Transmit Clock Pins



 Receive Clock 






Figure 14.	 Receive Clock



 External Clock Pins



Note:  Some remote connections do not provide transmit clock on pins U, W. When the TX 2000/TX 3000 board is acting as a DCE device and cannot transmit or receive data, positions 2 and 3 may be used together to tie the TX 2000/TX 3000 board's receive clock input to its own external transmit clock.




Figure 15.	 External Clock Pins












 
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