Switchboard Credit Card

Item Name: Switchboard Credit Card
Author(s): John J. Godfrey, Ed Holliman
LDC Catalog No.: LDC93S8
ISBN: 1-58563-016-0
ISLRN: 427-743-343-017-3
DOI: https://doi.org/10.35111/cmtf-v363
Member Year(s): 1993
DCMI Type(s): Sound
Sample Type: 2-channel ulaw
Sample Rate: 8000
Data Source(s): telephone conversations
Project(s): NIST SRE
Application(s): speech recognition
Language(s): English
Language ID(s): eng
License(s): LDC User Agreement for Non-Members
Online Documentation: LDC93S8 Documents
Licensing Instructions: Subscription & Standard Members, and Non-Members
Citation: Godfrey, John J., and Ed Holliman. Switchboard Credit Card LDC93S8. Web Download. Philadelphia: Linguistic Data Consortium, 1993.
Related Works: View


Switchboard Credit Card was developed by NIST and contains approximately eight hours of audio on the topic of "Credit Card Use" from the Switchboard corpus. This publication also includes transcriptions, time-alignments and wordspotting targets.

The full Switchboard corpus (LDC97S62) is a collection of about 2,400 two-sided telephone conversations among 543 speakers (302 male, 241 female) from all areas of the United States. A computer-driven robot operator system handled the calls, giving the caller appropriate recorded prompts, selecting and dialing another person (the callee) to take part in a conversation, introducing a topic for discussion and recording the speech from the two subjects into separate channels until the conversation was finished. About 70 topics were provided, of which about 50 were used frequently. Selection of topics and callees was constrained so that: (1) no two speakers would converse together more than once and (2) no one spoke more than once on a given topic. It was originally collected by Texas Instruments in 1990-1, under DARPA sponsorship. The first release of the corpus was published by NIST.


Audio files are presented as two-channel, 8-bit, 8 kHz u-law encoded audio waveform files with standard NIST SPHERE headers.

Transcriptions are text files containing interleaved transcriptions of both channels. Their headers describe various parameters of the conversation. Time-alignment files list out the individually transcribed words with their start times and durations. Wordspotting target files contain a reference list of occurrences for a key word.



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