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    Understanding IP-223 Jumper Settings


    How can I better understand IP-223 jumper settings?



    IP-223 jumper settings allow a great deal of flexibility in regards to the range of uses for the device.  Correct jumper settings are critical to every application.  Although many Telex application notes specify the required jumper settings for certain types of radio models, some radios are not covered and the technician must determine which settings are correct for their particular application.

    Explanations on the purpose of the settings are expanded upon here to assist in determining the best configuration.  Refer to the jumper chart in the IP-223 manual to idenfity specific jumper numbers based on the PCB revision. 

    2 Wire vs. 4 Wire
    Four wire mode consists of two pairs of conductors, one for TX, one for RX.  In the 2 wire form, the TX and RX signals are summed onto the same wire pair, which conserves resources but can also create problems in certain circumstances, and is generally more difficult to obtain a stable alignment with.  4 wire mode generally produces better quality audio than 2 wire mode.

    Balanced vs. Single Ended
    Locally controlled mobile radios are typically high impedance, single ended input and output lines.  Single ended refers to an unbalanced signal pair, in which one conductor is grounded and the other carries the AC signal above ground potential.  Radio audio impedances are generally considerably higher than 600 ohms, and may be 10K or greater. 

    Balanced audio refers to two conductors that provide forward and return paths, neither of which is referenced to ground.  Check specifications on your radio to determine which mode of connection is applicable.

    RX Input Impedance
    RX impedance may be 8 ohms, 600 ohms, or 10K ohms, depending on the source used.  A connection to a speaker for example would be 8 ohms.  Again, check the radio specifications to confirm the optimal value to be used.

    TX Output
    The transmit output level range has two options:  High or Low.  High is the most common value, but low may be required in certain systems requiring lower output levels. 

    Digital I/O Pull Up Voltage
    This jumper determines the pull up voltage for BCD (Binary Coded Decimal) channel steering bit lines.  It may be set for +5 volts, or floating (jumper set to hang on center pin).  This setting is determined by the radio requirements.  This jumper is only applicable to radios requiring BCD control.

    This jumper needs to stay in the "B" position.  (It is intended for a future feature in the IP-223)

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    Last update:
    ‎04-08-2020 07:11 PM
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