INTERNATIONAL TELECOMMUNICATION UNION
`
`CCITT
`
`THE INTERNATIONAL
`TELEGRAPH AND TELEPHONE
`CONSULTATIVE COMMITTEE
`
`V.32 bis
`
`DATA COMMUNICATION
`OVER THE TELEPHONE NETWORK
`
`A DUPLEX MODEM OPERATING AT
`DATA SIGNALLING RATES OF UP TO
`14 400 bit/s FOR USE ON THE GENERAL
`SWITCHED TELEPHONE NETWORK AND
`ON LEASED POINT-TO-POINT 2-WIRE
`TELEPHONE-TYPE CIRCUITS
`
`Recommendation V.32 bis
`
`Geneva, 1991
`
`CommScope, Inc.
`IPR2023-00066, Ex. 1015
`Page 1 of 24
`
`

`

`FOREWORD
`
`The CCITT (the International Telegraph and Telephone Consultative Committee) is a permanent organ of the
`International Telecommunication Union (ITU). CCITT is responsible for studying technical, operating and tariff
`questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide
`basis.
`
`The Plenary Assembly of CCITT which meets every four years, establishes the topics for study and approves
`Recommendations prepared by its Study Groups. The approval of Recommendations by the members of CCITT between
`Plenary Assemblies is covered by the procedure laid down in CCITT Resolution No. 2 (Melbourne, 1988).
`
`Recommendation V.32 bis was prepared by Study Group XVII and was approved under the Resolution No. 2
`procedure on the 22 of February 1991.
`
`___________________
`
`CCITT NOTE
`
`In this Recommendation, the expression “Administration” is used for conciseness to indicate both a
`telecommunication Administration and a recognized private operating agency.
`
`All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or
`mechanical, including photocopying and microfilm, without permission in writing from the ITU.
`
`ª ITU 1991
`
`CommScope, Inc.
`IPR2023-00066, Ex. 1015
`Page 2 of 24
`
`

`

`Recommendation V.32 bis
`
`Recommendation V.32 bis
`
`A DUPLEX MODEM OPERATING AT DATA SIGNALLING RATES OF UP TO
`14 400 bit/s FOR USE ON THE GENERAL SWITCHED TELEPHONE
`NETWORK AND ON LEASED POINT-TO-POINT 2-WIRE
`TELEPHONE -TYPE CIRCUITS
`
`1
`
`Introduction
`
`This modem is intended for use on connections on general switched telephone networks (GSTNs) and on
`point-to-point 2-wire leased telephone-type circuits. The principal characteristics of the modem are as follows:
`
`a)
`
`b)
`
`c)
`
`d)
`
`e)
`
`f)
`
`g)
`
`duplex mode of operation on GSTN and point-to-point 2-wire leased circuits;
`
`channel separation by echo cancellation techniques;
`
`quadrature amplitude modulation for each channel with synchronous line transmission at 2400 symbols/s;
`
`the following synchronous data signalling rates shall be implemented in the modem:
`
`–
`
`–
`
`–
`
`–
`
`–
`
`14 400 bit/s trellis coded,
`
`12 000 bit/s trellis coded,
`
`9600 bit/s trellis coded,
`
`7200 bit/s trellis coded,
`
`4800 bit/s uncoded;
`
`compatibility with Recommendation V.32 modems at 9600 and 4800 bit/s;
`
`exchange of rate sequences during start-up to establish the data signalling rate;
`
`a procedure to change the data signalling rate without retraining.
`
`Note 1 – On international GSTN connections that utilize circuits that are in accord with Recommen-
`dation G.235 (16-channel terminal equipments), it may be necessary to employ a greater degree of equalization within
`the modem than would be required for use on most national GSTN connections.
`
`Note 2 – The transmit and receive rates in each modem shall be the same. The possibility of asymmetric
`working remains for further study.
`
`2
`
`Line signals
`
`2.1
`
`Carrier frequency and modulation rate
`
`The carrier frequency is to be 1800 –
`frequency offset of up to –
` 7 Hz.
`
` 1 Hz. The receiver must be able to operate with a maximum received
`
`The modulation rate shall be 2400 symbols/s –
`
` 0.01%.
`
`2.2
`
`Transmitted spectrum
`
`The transmitted power level must conform to Recommendation V.2. With continuous binary ones applied to
`the input of the scrambler, the transmitted energy density at 600 Hz and 3000 Hz shall be attenuated 4.5 –
` 2.5 dB with
`respect to the maximum energy density between 600 Hz and 3 000 Hz.
`
`Recommendation V.32 bis
`
`1
`
`CommScope, Inc.
`IPR2023-00066, Ex. 1015
`Page 3 of 24
`
`

`

`2.3
`
`Coding
`
`2.3.1
`
`Signal element coding for 14 400 bit/s
`
`At 14 400 bits per second, the scrambled data stream to be transmitted is divided into groups of six
`consecutive data bits. The first two bits in time Q1n and Q2n in each group, where the subscript n designates the
`sequence number of the group, are first differentially encoded into Y1n and Y2n according to Table 1/V.32 bis. The two
`differentially encoded bits Y1n and Y2n are used as input to a systematic convolutional encoder which generates a
`redundant bit Y0n (see Figure 1/V.32 bis). This redundant bit and the six information-carrying bits Y1n, Y2n, Q3n, Q4n,
`Q5n, Q6n are then mapped into the coordinates of the signal element to be transmitted according to the signal space
`diagram shown in Figure 2-1/V.32 bis.
`
`TABLE 1/V.32 bis
`
`Differential quadrant coding with trellis coding
`
`Inputs
`
`Previous outputs
`
`Outputs
`
`Q1n
`
`Q2n
`
`Y1n- 1
`
`Y2n- 1
`
`Y1n
`
`Y2n
`
`0
`0
`0
`0
`
`0
`0
`0
`0
`
`1
`1
`1
`1
`
`1
`1
`1
`1
`
`0
`0
`0
`0
`
`1
`1
`1
`1
`
`0
`0
`0
`0
`
`1
`1
`1
`1
`
`0
`0
`1
`1
`
`0
`0
`1
`1
`
`0
`0
`1
`1
`
`0
`0
`1
`1
`
`0
`1
`0
`1
`
`0
`1
`0
`1
`
`0
`1
`0
`1
`
`0
`1
`0
`1
`
`0
`0
`1
`1
`
`0
`0
`1
`1
`
`1
`1
`0
`0
`
`1
`1
`0
`0
`
`0
`1
`0
`1
`
`1
`0
`1
`0
`
`0
`1
`1
`0
`
`1
`0
`0
`1
`
`2.3.2
`
`Signal element coding for 12 000 bit/s
`
`At 12 000 bits per second, the scrambled data stream to be transmitted is divided into groups of five
`consecutive data bits. The first two bits in time Q1n and Q2n in each group, where the subscript n designates the
`sequence number of the group, are first differentially encoded into Y1n and Y2n according to Table 1/V.32 bis. The two
`differentially encoded bits Y1n and Y2n are used as input to a systematic convolutional encoder which generates a
`redundant bit Y0n (see Figure 1/V.32 bis). This redundant bit and the five information-carrying bits Y1n, Y2n, Q3n, Q4n,
`Q5n, are then mapped into the coordinates of the signal element to be transmitted according to the signal space diagram
`shown in Figure 2-2/V.32 bis.
`
`2
`
`Recommendation V.32 bis
`
`CommScope, Inc.
`IPR2023-00066, Ex. 1015
`Page 4 of 24
`
`

`

`14 400 bit/s
`
`14 400 and 12 000 bit/s
`
`14 400, 12 000 and 9600 bit/s
`
`14 400, 12 000, 9600 and 7200 bit/s
`
`nQ6
`
`Q5
`
`n
`
`Q4
`
`n
`
`Q3
`
`n
`
`Q2
`
`n
`
`Q1n
`
`Table
`1/V.32 BIS
`
`nQ6
`
`Q5
`
`n
`
`Q4
`
`n
`
`Q3
`
`n
`
`Y2
`
`n
`
`Y1
`
`n
`
`+
`
`T
`
`+
`
`+
`
`T
`
`nY0
`
`T1701300-90
`
`Symbol truth table
`
`FIGURE 1/V.32 bis
`Trellis encoder
`
`T
`
`T
`
`+
`
`+
`
`T
`
`b
`
`0
`
`1
`
`0
`
`1
`
`s1
`
`s2
`
`0
`
`1
`
`1
`
`0
`
`0
`
`0
`
`0
`
`1
`
`a
`
`0
`
`0
`
`11
`
`s1
`
`s2
`
`b
`
`+
`
`a
`
`a
`
`b
`
`Recommendation V.32 bis
`
`3
`
`CommScope, Inc.
`IPR2023-00066, Ex. 1015
`Page 5 of 24
`
`

`

`0110000
`
`90°
`
`(Im)
`
`8
`
`0111000
`
`1100000
`
`1111001
`
`1101000
`
`1110001
`
`0010011
`
`0010111
`6
`
`0100001
`
`0010101
`
`0101001
`D
`
`1011101
`
`1000011
`
`1011111
`
`1000111
`
`1011011
`
`1000101
`
`0110101
`
`0001101
`
`0110100
`
`0001111
`4
`
`0111100
`
`0001011
`
`0111101
`
`1100101
`
`1111011
`
`1100100
`
`1111010
`
`1101100
`
`1110010
`
`1101101
`
`1110011
`
`0010001
`
`0101011
`
`0010010
`
`0101010
`
`0010110
`2
`
`0100010
`
`0010100
`
`0100011
`
`0010000
`
`1011000
`
`1000001
`
`1011100
`
`1000010
`
`1011110
`
`1000110
`
`1011010
`
`1000100
`
`C
`
`1011001
`
`1000000
`
`0001000
`-8
`
`0110111
`-6
`1100111
`
`0001100
`-4
`1111111
`
`0110110
`-2
`1100110
`
`0001110
`
`1111110
`
`180°
`
`0001010
`4
`
`0111111
`6
`
`1101111
`
`(Re)
`
`0°
`
`0011001
`
`0101111
`A
`
`1010000
`
`1001001
`
`1010100
`
`1001010
`
`0111110
`2
`1101110
`
`1110110
`
`0001001
`8
`1110111
`
`0011010
`
`0101110
`
`0100110
`
`0011100
`
`0100111
`
`0011000
`
`0011110
`-2
`1001110
`
`1010110
`
`1010010
`
`1001100
`
`1010001
`
`1001000
`
`0000000
`
`0110011
`
`0000100
`
`0110010
`
`0111010
`
`0000010
`
`0111011
`
`0000001
`
`1100011
`
`1111101
`
`1100010
`
`1111100
`
`1110100
`
`1101011
`
`1110101
`
`0000110
`-4
`1101010
`
`0101101
`
`0011011
`
`0101100
`
`0100100
`
`0011101
`
`0100101
`
`1010101
`
`1001011
`
`1010111
`
`B
`
`1010011
`
`1001101
`
`0011111
`-6
`1001111
`
`0000101
`
`0110001
`
`0111001
`
`0000011
`
`0000111
`-8
`1101001
`
`1100001
`
`1111000
`
`1110000
`
`0101000
`
`270°
`
`0100000
`
`T1701310-90
`
`Note – Binary numbers refer to Y0 , Y1 , Y2 , Q3 , Q4 , Q5 , Q6 .
`n
`n
`n
`n
`n
`n
`n
`A, B, C, D refer to synchronizing signal elements.
`
`FIGURE 2-1/V.32 bis
`Signal space diagram and mapping for modulation at 14 400 bit/s per second
`
`4
`
`Recommendation V.32 bis
`
`CommScope, Inc.
`IPR2023-00066, Ex. 1015
`Page 6 of 24
`
`

`

`001010
`
`100010
`
`011111
`
`90°
`111000
`
`D
`
`101011
`
`000011
`
`110111
`
`010000
`
`011110
`
`111001
`
`001100
`
`100100
`
`6
`
`4
`
`2
`
`(Im)
`
`001110
`
`100110
`
`011011
`
`111010
`
`101001
`
`000001
`
`110011
`
`010010
`
`011101
`
`111100
`
`001111
`
`100111
`
`110110
`
`-6
`
`010001
`
`-4
`
`101101
`
`-2
`
`000101
`
`110101
`
`2
`
`010100
`
`4
`
`101000
`
`180°
`
`001000
`
`A
`
`100000
`
`011100
`
`111101
`
`001101
`
`100101
`
`011001
`
`111110
`
`–2
`
`C
`
`6
`
`000000
`(Re)
`0°
`
`101111
`
`000111
`
`110100
`
`010101
`
`101100
`
`000100
`
`110001
`
`010110
`
`011010
`
`111011
`
`001001
`
`100001
`
`–4
`
`011000
`–6
`
`B
`
`111111
`
`001011
`
`100011
`
`110010
`
`010011
`
`101110
`
`000110
`
`110000
`
`010111
`
`101010
`
`000010
`
`270°
`
`T1701320-90
`
`Note – Binary numbers refer to Y0 , Y1 , Y2 , Q3 , Q4 , Q5 .
`n
`n
`n
`n
`n
`n
`A, B, C, D refer to synchronizing signal elements.
`
`FIGURE 2-2/V.32 bis
`Signal space diagram and mapping for modulation at 12 000 bit/s per second
`
`2.3.3
`
`Signal element coding for 9600 bit/s
`
`At 9600 bits per second, the scrambled data stream to be transmitted is divided into groups of four consecutive
`data bits. The first two bits in time Q1n and Q2n in each group, where the subscript n designates the sequence number of
`the group, are first differentially encoded into Y1n and Y2n according to Table 1/V.32 bis. The two differentially
`encoded bits Y1n and Y2n are used as input to a systematic convolutional encoder which generates a redundant bit Y0n
`(see Figure 1/V.32 bis). This redundant bit and the four information-carrying bits Y1n, Y2n, Q3n, Q4n, are then mapped
`into the coordinates of the signal element to be transmitted according to the signal space diagram shown in Figure 2-
`3/V.32 bis.
`
`2.3.4
`
`Signal element coding for 7200 bit/s
`
`At 7200 bits per second, the scrambled data stream to be transmitted is divided into groups of three
`consecutive data bits. The first two bits in time Q1n and Q2n in each group, where the subscript n designates the
`sequence number of the group, are first differentially encoded into Y1n and Y2n according to Table 1/V.32 bis. The two
`differentially encoded bits Y1n and Y2n are used as input to a systematic convolutional encoder which generates a
`redundant bit Y0n (see Figure 1/V.32 bis). This redundant bit and the three information-carrying bits Y1n, Y2n, Q3n, are
`then mapped into the coordinates of the signal element to be transmitted according to the signal space diagram shown in
`Figure 2-4/V.32 bis.
`
`Recommendation V.32 bis
`
`5
`
`CommScope, Inc.
`IPR2023-00066, Ex. 1015
`Page 7 of 24
`
`

`

`(Im)
`
`90°
`
`4
`
`11111
`
`11000
`
`01000
`
`D
`
`00101
`
`01010
`
`10010
`
`10101
`
`10011
`
`10100
`
`2
`
`00000
`-4
`
`180°
`
`01111
`-2
`
`00010
`
`C
`
`01101
`2
`
`00011
`4
`
`11001
`
`11110
`
`11010
`
`11101
`
`(Re)
`0°
`
`A
`
`00111
`
`01001
`
`00110
`
`01011
`
`00100
`
`10000
`
`10111
`
`10001
`
`10110
`
`–2
`
`01110
`
`00001
`
`B
`
`01100
`
`–4
`
`11100
`
`11011
`
`270°
`
`T1701330-90
`
`Note – Binary numbers refer to Y0 , Y1 , Y2 , Q3 , Q4 .
`n
`n
`n
`n
`n
`A, B, C, D refer to synchronizing signal elements.
`
`FIGURE 2-3/V.32 bis
`Signal space diagram and mapping for modulation at 9600 bit/s per second
`
`0010
`
`90°
`
`D
`1000
`
`(Im)
`
`0111
`
`1110
`
`2
`
`1011
`
`–2
`
`0001
`
`1101
`
`C
`0100
`
`2
`
`(Re)
`0°
`
`180°
`
`A
`0110
`
`1111
`
`0011
`
`1001
`
`–2
`
`B
`1010
`
`270°
`
`1100
`
`0101
`
`0000
`
`T1701340-90
`
`Note – Binary numbers refer to Y0 , Y1 , Y2 .
`n
`n
`n
`A, B, C, D refer to synchronizing signal elements.
`
`FIGURE 2-4/V.32 bis
`Signal space diagram and mapping for modulation at 7200 bit/s per second
`
`6
`
`Recommendation V.32 bis
`
`CommScope, Inc.
`IPR2023-00066, Ex. 1015
`Page 8 of 24
`
`

`

`2.3.5
`
`Signal element coding for 4800 bit/s
`
`At 4800 bits per second, the scrambled data stream to be transmitted is divided into groups of two consecutive
`data bits. The two bits Q1n and Q2n, where Q1n is first in time, where the subscript n designates the sequence number of
`the group, are first differentially encoded into Y1n and Y2n according to Table 2/V.32 bis. The two differentially
`encoded bits Y1n and Y2n are then mapped into the coordinates of the signal element to be transmitted according to the
`signal space diagram shown in Figure 2-5/V.32 bis.
`
`TABLE 2/V.32 bis
`
`Differential quadrant coding for 4800 bit/s
`
`Inputs
`
`Previous outputs
`
`Q1n
`
`Q2n
`
`Y1n- 1
`
`Y2n- 1
`
`Phase quadrant
`change
`
`Outputs
`
`Y1n
`
`Y2n
`
`Signal state for
`4800 bit/s
`
`0
`0
`0
`0
`
`0
`0
`0
`0
`
`1
`1
`1
`1
`
`1
`1
`1
`1
`
`0
`0
`0
`0
`
`1
`1
`1
`1
`
`0
`0
`0
`0
`
`1
`1
`1
`1
`
`0
`0
`1
`1
`
`0
`0
`1
`1
`
`0
`0
`1
`1
`
`0
`0
`1
`1
`
`0
`1
`0
`1
`
`0
`1
`0
`1
`
`0
`1
`0
`1
`
`0
`1
`0
`1
`
`+90°
`
`0°
`
`+180°
`
`+270°
`
`0
`1
`0
`1
`
`0
`0
`1
`1
`
`1
`1
`0
`0
`
`1
`0
`1
`0
`
`1
`1
`0
`0
`
`0
`1
`0
`1
`
`1
`0
`1
`0
`
`0
`0
`1
`1
`
`B
`C
`A
`D
`
`A
`B
`D
`C
`
`C
`D
`B
`A
`
`D
`A
`C
`B
`
`(Im)
`
`90°
`
`4
`
`2
`
`D
`10
`
`–2
`
`–4
`
`B
`01
`
`270°
`
`180°
`
`–4
`
`–2
`
`A
`00
`
`C
`11
`
`2
`
`4
`
`(Re)
`0°
`
`T1701350-90
`
`Note – Binary numbers refer to Y1 and Y2 .
`n
`n
`A, B, C, D refer to synchronizing signal elements.
`
`FIGURE 2-5/V.32 bis
`
`Signal space diagram and mapping for modulation at 4800 bit/s per second
`
`Recommendation V.32 bis
`
`7
`
`CommScope, Inc.
`IPR2023-00066, Ex. 1015
`Page 9 of 24
`
`

`

`3
`
`DTE interface
`
`When a standardized physical interface for the interchange circuits is not present, the equivalent functionality
`of the circuits must still be provided (see Table 3/V.32 bis).
`
`TABLE 3/V.32 bis
`
`Interchange circuit
`
`Description
`
`Signal ground or common return
`Transmitted data
`Received data
`Request to send
`Ready for sending
`
`No.
`
`102
`103
`104
`105
`106
`
`107
`108/1 or
`108/2
`109
`
`Data set ready
`Connect data set to line
`Data terminal ready
`Data channel received line signal detector
`
`113
`114
`115
`125
`140
`141
`142
`
`Transmitter signal element timing (DTE source)
`Transmitter signal element timing (DCE source)
`Receiver signal element timing (DCE source)
`Calling indicator
`Loopback/maintenance
`Local loopback
`Test indicator
`
`Note 1
`Note 1
`
`Note 2
`
`Note 3
`Note 3
`
`Note 1 – This circuit shall be capable of operation as circuit 108/1 or circuit 108/2 depending on its use. Operation of
`circuits 107 and 108/1 shall be in accordance with § 4.4 of Recommendation V.24.
`Note 2 – When the modem is not operating in a synchronous mode at the interface, any signals on this circuit shall be
`disregarded. Many DTEs operating in an asynchronous mode do not have a generator connected to this circuit.
`Note 3 – When the modem is not operating in a synchronous mode at the interface, this circuit shall be clamped to
`the OFF condition. Many DTEs operating in an asynchronous mode do not terminate this circuit.
`
`3.1
`
`Synchronous interfacing
`
`The modems shall accept synchronous data from the DTE on circuit 103 (see Recommendation V.24) under
`control of circuit 113 or 114. The modem shall pass synchronous data to the DTE on circuit 104 under the control of
`circuit 115. The modem shall provide to the DTE, a clock on circuit 114 for transmit-data timing, and a clock on
`circuit 115 for receive-data timing. The transmit-data timing may, however, originate in the DTE and be transferred to
`the modem via circuit 113. In some applications, it may be necessary to slave the transmitter timing to the receiver
`timing inside the modem.
`
`After the start-up and retrain sequences, circuit 106 must follow the state of circuit 105 within 2 ms.
`
`OFF to ON and ON to OFF transitions of circuit 109 should occur solely in accordance with the operating
`sequences defined in § 5. Thresholds and response times are inapplicable because a line signal detector cannot be
`expected to distinguish wanted received signals from unwanted talker echos.
`
`8
`
`Recommendation V.32 bis
`
`CommScope, Inc.
`IPR2023-00066, Ex. 1015
`Page 10 of 24
`
`

`

`3.2
`
`Asynchronous character-mode interfacing
`
`The modulation process operates synchronously. However, the modem may be associated with an
`asynchronous to synchronous conversion entity interfacing to the DTE in an asynchronous (or start-stop character)
`mode. The protocol for conversion shall be in accordance with Recommendations V.14 or V.42. Other facilities such as
`data compression may also be employed.
`
`3.3
`
`Electrical characteristics of interchange circuits
`
`to
`the electrical characteristics conforming
`is provided,
`interface
`When a standardized physical
`to
`the electrical characteristics conforming
`Recommendation V.28 will normally be used. Alternatively,
`Recommendations V.10 and V.11 may be used. The connector and pole assignments specified by ISO 2110,
`corresponding to the electrical characteristics provided, shall be used.
`
`3.4
`
`Fault condition on interchange circuits
`
`The DTE shall interpret a fault condition on circuit 107 as an OFF condition using failure detection type 1.
`
`The DCE shall interpret a fault condition on circuits 105 and 108 as an OFF condition using failure detection
`
`type 1.
`
`All other circuits not referred to may use failure detection types 0 or 1.
`
`Note – See § 7 of Recommendation V.28 and § 11 of Recommendation V.10.
`
`4
`
`Scrambler and descrambler
`
`A self-sychronizing scrambler/descrambler shall be included in the modem. Each transmission direction uses a
`different scrambler. The method of allocating the scramblers is described in § 4.1. According to the direction of
`transmission, the generating polynomial is:
`
`Call mode modem generating polynomial: (GPC) = 1 + x–18 + x–23, or
`
`Answer mode modem generating polynomial: (GPA) = 1 + x–5 + x–23
`
`At the transmitter, the scrambler shall effectively divide the message data sequence by the generating
`polynomial. The coefficients of the quotients of this division, taken in descending order, form the data sequence which
`shall appear at the output of the scrambler. At the receiver, the received data sequence shall be multiplied by the
`scrambler generating polynomial to recover the message sequence.
`
`4.1
`
`Scrambler/descrambler allocation
`
`On the general switched telephone network, the modem at the calling data station (call mode) shall use the
`scrambler with the GPC generating polynomial and the descrambler with the GPA generating polynomial. The modem
`at the answering data station (answer mode) shall use the scrambler with the GPA generating polynomial and the
`descrambler with the GPC generating polynomial. On point-to-point leased circuits or when calls are established on the
`GSTN by operators, call mode/answer mode designation will be by bilateral agreement between Administrations or
`users and the scrambler/descrambler allocation will be the same as used on the GSTN.
`
`5
`
`Operating procedures
`
`5.1
`
`Recommendation V.25 automatic answering sequence
`
`The Recommendation V.25 automatic answering sequence shall be transmitted from the answer mode modem
`on GSTN connections. The transmission of the sequence may be omitted on point-to-point leased circuits. In this event,
`the modem shall initiate transmission as in the retrain procedure specified in § 7.
`
`Recommendation V.32 bis
`
`9
`
`CommScope, Inc.
`IPR2023-00066, Ex. 1015
`Page 11 of 24
`
`

`

`5.2
`
`Receiver conditioning signal
`
`The receiver conditioning signal shall be used in the start-up and retrain procedures defined in §§ 6 and 7
`below. The signal consists of three segments:
`
`Segment 1, denoted by S in Figures 3/V.32 bis and 4/V.32 bis consists of alternations between states A and B
`5.2.1
`as shown in Figure 2-5/V.32 bis, for a duration of 256 symbol intervals.
`
`Call
`mode
`modem
`
`³
` 1 second
`
`64T ± 2T
`
`AA
`
`CC
`
`NT
`
`NT
`
`256T
`
`1280T
`
`8T 128T
`
`S
`
`S S TRN
`
`Rate signal R2
`
`E
`
`B1
`
`Data
`
`16T
`
`Note
`
`107
`
`106
`
`Unclamp 104
`
`109
`
`64T
`
`MT
`
`Note
`
`16T
`
`16T
`
`128T
`
`Answer
`mode
`modem
`
`ANS
`
`AC
`
`CA
`
`AC
`
`S S TRN
`
`R1
`
`S S TRN
`
`R3
`
`E
`
`B1
`
`Data
`
`V25
`
`128T
`
`64T ± 2T
`
`16T
`
`256T
`
`1280T
`
`256T
`
`1280T
`
`8T
`
`106
`
`107
`
`Unclamp 104
`
`109
`T1701530-92/d07
`
`Signal states ACAC..AC for an even number of symbol intervals T; similarly with CA, AA and CC
`Round-trip delays observed from answer and call modems respectively, including 64T ± 2T modem turn round delay
`Signal states ABAB..AB, CDCD..CD
`Scrambled ones at 4800 bit/s with dibits encoded directly to states A, B, C and D as defined in § 5.2
`Each a repeated 16-bit rate sequence at 4800 bit/s scrambled and differentially encoded as in Table 2/V.32 BIS
`A single 16-bit sequence marking and following the end of a whole number of 16-bit rate sequences in R2 and R3
`Binary ones scrambled and encoded as for the subsequent transmission of data
`
`AC
`MT, NT
`S, S
`TRN
`R1, R2, R3
`
`1
`
`EB
`
`Note – The inclusion of a special echo canceller training sequence at this point is optional (see § 6, Note 3).
`
`FIGURE 3/V.32 bis
`Start-up procedure
`
`Segment 2, denoted by S in Figures 3/V.32 bis and 4/V.32 bis consists of alternations between states C and D
`
`5.2.2
`as shown in Figure 2-5/V.32 bis, for a duration of 16 symbol intervals.
`
`Note – The transition from segment 1 to segment 2 provides a well-defined event in the signal that may be
`used for generating a time reference in the receiver.
`
`10
`
`Recommendation V.32 bis
`
`CommScope, Inc.
`IPR2023-00066, Ex. 1015
`Page 12 of 24
`
`‡
`‡
`‡
`‡
`‡
`-
`

`

`Call
`mode
`modem
`Data
`
`Answer
`mode
`modem
`Data
`
`64T ± 2T
`
`NT
`
`256T
`
`1280T
`
`8T 128T
`
`AA
`
`106
`
`Clamp 104
`
`CC
`
`NT
`
`S
`
`S S TRN
`
`Rate signal R2
`
`E
`
`B1
`
`Data
`
`16T
`
`Note
`
`106
`
`Unclamp 104
`
`128T
`
`64T MT
`
`Note
`
`16T
`
`16T
`
`128T
`
`AC
`
`CA
`
`AC
`
`S S TRN
`
`R1
`
`S S TRN
`
`R3
`
`E
`
`B1
`
`Data
`
`106
`
`64T ± 2T
`Clamp 104
`
`16T
`
`256T
`
`1280T
`
`256T
`
`1280T
`
`8T
`
`106
`
`Unclamp 104
`
`A 2ETRAININITIATEDBYTHECALLINGMODEM
`
`128T
`
`64T ± 2T
`
`NT
`
`256T
`
`1280T
`
`Call
`mode
`modem
`Data
`
`Answer
`mode
`modem
`Data
`
`8T 128T
`
`S
`
`S S TRN
`
`Rate signal R2
`
`E
`
`B1
`
`Data
`
`Note
`
`16T
`
`106
`
`Unclamp 104
`
`CC
`
`NT
`
`AA
`
`106
`
`Clamp 104
`
`64T
`
`MT
`
`Note
`
`16T
`
`16T
`
`128T
`
`AC
`
`CA
`
`AC
`
`S S TRN
`
`R1
`
`S S TRN
`
`R3
`
`E
`
`B1
`
`Data
`
`106
`
`64T ± 2T
`Clamp 104
`
`16T
`
`256T
`
`1280T
`
`256T
`
`1280T
`
`8T
`
`B 2ETRAININITIATEDBYTHEANSWERINGMODEM
`
`106
`
`Unclamp 104
`
`T1701540-92/d08
`
`Signal states ACAC..AC for an even number of symbol intervals T; similarly with CA, AA and CC
`Round-trip delays observed from answer and call modems respectively, including 64T ± 2T modem turn round delay
`Signal states ABAB..AB, CDCD..CD
`Scrambled ones at 4800 bit/s with dibits encoded directly to states A, B, C and D as defined in § 5.2
`Each a repeated 16-bit rate sequence at 4800 bit/s scrambled and differentially encoded as in Table 2/V.32 BIS
`A single 16-bit sequence marking and following the end of a whole number of 16-bit rate sequences in R2 and R3
`Binary ones scrambled and encoded as for the subsequent transmission of data
`
`AC
`MT, NT
`S, S
`TRN
`R1, R2, R3
`
`1
`
`EB
`
`Note – The inclusion of a special echo canceller training sequence at this point is optional (see § 6, Note 3).
`
`FIGURE 4/V.32 bis
`Retrain procedure
`
`Recommendation V.32 bis
`
`11
`
`CommScope, Inc.
`IPR2023-00066, Ex. 1015
`Page 13 of 24
`
`‡
`‡
`‡
`‡
`‡
`‡
`‡
`‡
`‡
`‡
`

`

`Segment 3, denoted by TRN in Figures 3/V.32 bis and 4/V.32 bis, is a sequence derived by scrambling binary
`5.2.3
`ones at a data rate of 4800 bit/s with the scrambler defined in § 4. During the transmission of this segment, the
`differential quadrant encoding shall be disabled. The initial state of the scrambler shall be all zeros, and a binary one
`applied to the input for the duration of segment 3. Successive dibits are encoded onto transmitted signal states.
`
`The first 256 transmitted signal states are determined from the state of the first bit occurring (in time) in each
`dibit. When this bit is ZERO, signal state A is transmitted; when this bit is ONE, signal state C is transmitted. Depending
`on whether the modem is in call or answer mode, the scrambler output patterns and corresponding signal states will then
`begin as below, where the bits and the signal states are shown in time sequence from left to right.
`
`Call mode modem:
`
`GPC:,
`
`11 11 11 11 11 11 11 11 11 00 00 01 11 11 11
`C C C C C C C C C A A A C C C
`
`Answer mode modem:
`
`GPA:,
`
`11 11 10 00 00 11 11 10 00 00 11 10 01 11 11
`C C C A A C C C A A C C A C C
`
`Immediately after 256 such symbols, successive scrambled dibits are encoded onto transmitted signal states in
`accordance with Table 4/V.32 bis directly without differential encoding for the remainder of segment 3. The duration of
`segment 3 shall be at least 1280 and not exceed 8192 symbol intervals.
`
`Segment 3 is intended for training the adaptive equaliser in the receiving modem and the echo canceller in the
`transmitting modem.
`
`TABLE 4/V.32 bis
`
`Encoding for TRN segment
`after the first 256 symbols
`
`Dibit
`
`Signal state
`
`ABCD
`
`00
`01
`11
`10
`
`5.3
`
`Rate signal
`
`The rate signal shall be used in the start-up, retrain, and rate re-negotiating procedures.
`
`The rate signal consists of a whole number of repeated 16-bit binary sequences, as defined in Table 5/V.32 bis,
`scrambled and transmitted at 4800 bit/s with dibits differentially encoded as in Table 2/V.32 bis. In the start-up and
`retrain procedures (see §§ 6 and 7), the differential encoder shall be initialized using the final symbol of the transmitted
`TRN segment.
`
`In the rate renegotiation procedure (see § 8), the differential encoder shall be initialized using the final symbol
`of the transmitted preamble and the scrambler shall be initialized to all zeros.
`
`The first two bits and each successive dibit of the rate sequence shall be encoded to form the transmitted signal
`
`states.
`
`12
`
`Recommendation V.32 bis
`
`CommScope, Inc.
`IPR2023-00066, Ex. 1015
`Page 14 of 24
`
`

`

`TABLE 5/V.32 bis
`
`Coding of the rate signal
`
`· · ·
`
`B3
`
`0
`
`B2
`
`0
`
`B1
`
`0
`
`B0
`
`0
`
`B1
`
`5
`
`B1
`
`4
`
`B1
`
`3
`
`B1
`
`2
`
`B1
`
`1
`
`B1
`
`0
`
`-
`
`1
`
`-
`
`0
`
`0
`
`1
`
`B9
`
`-
`
`B8
`
`1
`
`B7
`
`1
`
`B6
`
`-
`
`B5
`
`-
`
`B4
`
`1
`
`B3
`
`0
`
`B2
`
`0
`
`B1
`
`0
`
`B0
`
`0
`
`For synchronizing on a rate signal
`B0-B3, B7, B11, B15
`= 1 (Note 1)
`B4
`= 1 (Note 1)
`B8
`1 denotes that operation at 4800 bit/s rate is enabled
`B5
`1 denotes that operation at 9600 bit/s rate is enabled
`B6
`1 denotes that operation at 7200 bit/s rate is enabled
`B9
`1 denotes that operation at 12 000 bit/s rate is enabled
`B10
`1 denotes that operation at 14 400 bit/s rate is enabled
`B12
`= 0, 0 (Note 2)
`B13, B14
`Note 1 – When B4 or B8 is set to zero, in a transmitted or received rate signal, then interworking can
`proceed only in accordance with Recommendation V.32.
`Note 2 – B13 and B14 shall be set to zero when transmitting and ignored during the reception of a rate
`signal; they are reserved for future definition by the CCITT and must not be used by manufacturers.
`Note 3 – B4-B6, B9-B10, B12 set to zero calls for a GSTN cleardown.
`
`5.3.1
`
`Detecting a rate signal
`
`The minimum requirement for detection is the receipt of two consecutive identical 16-bit sequences each with
`bits B0-B3, B7, B11 and B15 conforming to Table 5/V.32 bis.
`
`5.3.2
`
`Ending the rate signal
`
`In order to mark the end of transmission of any rate signal other then R1 (see Figure 3/V.32 bis), the modem
`shall first complete the transmission of the current 16-bit rate sequence, and then transmit one 16-bit sequence E, coded
`as shown in Table 6/V.32 bis.
`
`TABLE 6/V.32 bis
`
`Coding of sequence E
`
`B1
`
`5
`
`B1
`
`4
`
`B1
`
`3
`
`B1
`
`2
`
`B1
`
`1
`
`B1
`
`0
`
`-
`
`1
`
`-
`
`0
`
`0
`
`1
`
`B9
`
`-
`
`B8
`
`1
`
`B7
`
`1
`
`B6
`
`-
`
`B5
`
`-
`
`B4
`
`1
`
`B3
`
`1
`
`B2
`
`1
`
`B1
`
`1
`
`B0
`
`1
`
`B4-B12 as in Table 5/V.32 bis except the only data rate to be indicated shall relate to the transmission of
`scrambled binary ones immediately following signal E.
`
`Recommendation V.32 bis
`
`13
`
`CommScope, Inc.
`IPR2023-00066, Ex. 1015
`Page 15 of 24
`
`

`

`6
`
`Start-up procedure
`
`The procedure for achieving synchronism between the calling modem and the answering modem on
`international GSTN connections is shown in Figure 3/V.32 bis. the procedure includes the estimating of round-trip delay
`from each modem, the training of echo cancellers and receivers initially with half-duplex transmissions, and the
`exchanging of rate signals for automatic bit-rate and mode selection.
`
`6.1
`
`Call mode modem
`
`After receiving the answer tone for a period of at least 1 s as specified in Recommendation V.25, the modem
`shall be connected to line (see Note 1 below) and shall condition the scrambler and descrambler in accordance with
`§ 4.1.
`
`The modem shall repetively transmit carrier state A as shown in Figure 2-5/V.32 bis.
`
`The modem shall be conditioned to detect (see Note 2 below) one of two incoming tones at frequencies
` 7 Hz and 3000 –
` 7 Hz, and subsequently to detect a phase reversal in that tone.
`
`600 –
`
`On detection of one such phase reversal, the modem shall be conditioned to detect a second phase reversal in
`the same tone, start a counter/timer and change to repetively transmitting state C as shown in Figure 2-5/V.32 bis. The
`time delay between the reception of this phase reversal at the line terminals and the transmitted AA to CC transition
`appearing at the line terminals shall be 64 –
` 2 symbol periods.
`
`On detection of a second phase reversal in the same incoming tone, the modem shall stop the counter/timer and
`cease transmitting.
`
`When the modem detects an incoming S sequence (see § 5.2), it shall proceed to train its receiver, and then
`seek to detect at least two consecutive identical 16-bit rate sequences as defined in Table 5/V.32 bis.
`
`On detection of the rate signal (R1), the modem shall transmit an S sequence for a period NT already estimated
`by the counter/timer.
`
`After this period has expired (see Note 3 below), the modem shall transmit the receiver conditioning signal as
`defined in § 5.2, starting with an S sequence for 256 symbol intervals.
`
`Transmission of the TRN segment of the receiver conditioning signal may be extended in order to ensure a
`satisfactory level of echo cancellation (see Note 4 below).
`
`After the TRN segment, the modem shall apply an ON condition to circuit 107 and transmit a rate signal (R2)
`in accordance with § 5.3 to indicate the currently available data rates. R2 shall exclude rates not appearing in the
`previously received rate signal R1. It is recommended that R2 take also account of the likely receiver performance with
`the particular GSTN connection. If it appears that satisfactory performance cannot be attained at any of the available
`data rates, then R2 should be used to call for a GSTN cleardown in accordance with Table 5/V.32 bis.
`
`Transmission of R2 shall continue until an incoming rate signal R3 is detected. The modem shall then, after
`completing its current 16-bit rate sequence, transmit a single 16-bit sequence E in accordance with § 5.3.2 indicating the
`data rate called for in R3. If, however, R3 is calling for GSTN cleardown in accordance with Table 5/V.32 bis, then the
`call modem shall disconnect from line and effect a cleardown.
`
`The modem shall then transmit continuous scrambled binary ones at the data rate called for in R3. If trellis
`coding is to be used, the initial states of the delay elements of the convolution encoder shown in Figure 1/V.32 bis shall
`be set to zero.
`
`On detecting an incoming 16-bit E sequence as defined in § 5.3.2, the modem shall condition itself to receive
`data at the rate indicated by the incoming E sequence. After a delay of 128 symbol intervals, it shall apply an ON
`condition to circuit 109, and unclamp circuit 104.
`
`The modem shall then enable circuit 106 to respond to the condition of circuit 105 and be ready to transmit
`
`data.
`
`14
`
`Recommendation V.32 bis
`
`CommScope, Inc.
`IPR2023-00066, Ex. 1015
`Page 16 of 24
`
`

`

`6.2
`
`Answer mode modem
`
`On connection to line, the modem shall condition the scrambler and descrambler in accordance with § 4.1, and
`transmit the Recommendation V.25 answer sequence. Means, defined in Recommendation V.25, of disabling network
`cancellers and/or truncating the answer tone may be employed.
`
`After the Recommendation V.25 answer sequence, the modem shall transmit alternate carrier states A and C as
`shown in Figure 2-5/V.32 bis.
`
`After alternate states A and C have been transmitted for an even number of symbol intervals greater than or
`equal to 128 and an incoming tone has been detected at 1800 –
` 7 Hz for 64 symbol periods (see Note 5 below), the
`modem shall be conditioned to detect a phase reversal in the incoming tone, start a counter/timer, and change to
`transmitting alternate carrier states C and A for an even number of symbol intervals.
`
`On detecting a phase reversal in the incoming tone, the modem shall stop the counter/timer and, after
`transmitting a state A, revert to transmitting alternate states A and C. The time delay between the reception of this phase
`reversal at the line terminals and the transmitted CA to AC transition appearing at the line terminals shall be 64 –
` 2
`symbol periods.
`
`When an amplitude drop is detected in the incoming tone, the modem shall cease transmitting for a period of
`16 symbol intervals and then (see Note 3 below) transmit the receiver conditioning signal as defined in § 5.2.
`
`Transmission of the TRN segment of the receiver conditioning signal may be extended in order to ensure a
`satisfactory level of echo cancellation (see Note 4 below).
`
`After the TRN segment, the modem shall transmit a rate signal (R1) in accordance with § 5.3 to indicate the
`data rates currently available in the answer modem and associated DTE.
`
`On detection of an incoming S sequence,