TR-08 T1 Signalling Bits

Version 2
    Article ID: 1605
    Q&A

     

     

      TR-08 T1 Signalling Bits


     

    Q:

    TR-08 T1 Signalling Bits

     

     

    A:

    Introduction

    Signaling bits are used to indicate the progress of a voice call on a T1 circuit (Off-hook, On-hook, Ringing, Disconnect, etc...) These apply if you are using ADTRAN FXS/FXO/E&M voice modules. This note will explain the states of the signaling bits.

    Signaling Bit Charts

    Single Line Party

    (Loop Start)

     

    System Status

     

    TXA

     

    TXB

     

    RXA

     

    RXB

     

    Comments
    On-hook/IDLE0011Idle mode on T1 and 2W
    Off-hook on 2W10112W side is off-hook
    Call Complete1011Both 2W side and T1 is off-hook
    Incoming ringing0011/0T1 tells us to output ringing voltage
    Far End Disconnect----10Far end has went back on-hook; should pull battery, but 750 FXS and TSU FXS do NOT!
    Reverse Battery----1/01/0Telco tells us to reverse battery; only valid when Answer Supervision enabled
    Unequipped11----No card installed; not mapped
    Channel Test----01Telco has channel in a test mode
    Universal Voice Grade

    (UVG - Loop Start)

     

    System Status

     

    TXA

     

    TXB

     

    RXA

     

    RXB

     

    Comments
    On-hook0001/02W and T1 are on-hook
    Off-hook on 2W1001/02W side is off-hook
    Call Complete1001/0Both 2W side and T1 is off-hook
    Incoming ringing0011/0T1 tells us to output ringing voltage
    Far End Disconnect----00Far end has went back on-hook; pull battery from 2W
    Reverse Battery----1/01/0Telco tells us to reverse battery; only valid when Answer Supervision enabled
    Unequipped11----No card installed; not mapped
    Channel Test----01Telco has channel in a test mode
    Universal Voice Grade

    (UVG - Ground Start)

     

    System Status

     

    TXA

     

    TXB

     

    RXA

     

    RXB

     

    Comments
    On-hook00002W and T1 are on-hook; 2W TIP OPEN
    Ring ground01002W side detects ring ground
    Tip ground return0101/0Tip ground return detected from T1 side
    Off-hook/Loop closure1001/02W side detects loop closure
    Call Complete1001/0Connection established
    Incoming ringing----11/0T1 tells us to output ringing voltage
    Far End Disconnect----00Far end has went back on-hook; pull battery from 2W (TIP OPEN)
    Reverse Battery----1/01/0Telco tells us to reverse battery; only valid when Answer Supervision enabled
    Unequipped11----No card installed; not mapped
    Channel Test----01Telco has channel in a test mode

    If you experience any problems using your ADTRAN product, please contact ADTRAN Technical Support.