Switchboard Cellular Part 2 Audio

Item Name: Switchboard Cellular Part 2 Audio
Authors: David Graff, Kevin Walker, and David Miller
LDC Catalog No.: LDC2004S07
ISBN: 1-58563-297-x
Release Date: Oct 26, 2004
Data Type: speech
Sample Rate: 8000 Hz
Sampling Format: 2-channel ulaw
Data Source(s): telephone conversations
Project(s): EARS, GALE, SID
Application(s): language identification, speaker identification
Language(s): English
Language ID(s): eng
Distribution: 3 DVD
Member fee: $0 for 2004 members
Non-member Fee: US $6000.00
Reduced-License Fee: US $3000.00
Extra-Copy Fee: US $600.00
Non-member License: yes
Online documentation: yes
Licensing Instructions: Subscription & Standard Members, and Non-Members
Citation: David Graff, Kevin Walker, and David Miller
Switchboard Cellular Part 2 Audio
Linguistic Data Consortium, Philadelphia


Switchboard Cellular Part 2 Audio was produced by Linguistic Data Consortium (LDC) catalog number LDC2004S07 and ISBN 1-58563-297-x.

The Switchboard Cellular Part 2 Audio collection focused primarily on cellular phone technology (all service types). The collection commenced 09/16/2000 and was completed by 12/15/2000. The project's goal was to target 200 subjects, balanced by gender, under varied environmental conditions to participate in (10+) five-six minute conversations on cellular phones. The speech data was collected for research, development, and evaluation of automatic systems for speech-to-text conversion, talker identification, language identification and speech signal detection purposes.


This release contains speech data files only, along with documentation describing speaker information (sex, age, education, city and state where raised), call information (date, time, call duration, Personal Identification Numbers, topic), and audit information (channel quality, background noise). The documentation also contains reports on clipped files.

During the collection period, the LDC collected a total of 2,020 calls, or 4,040 sides (2,950 cellular, 2,405 female, 1,635 male), from 419 participants, under varied environmental conditions. There are a total of 2,020 speech files for a rough total of 202 hours of audio data (a little over 11 GB).

Each speech file consists of a 1,024-byte ASCII-formatted Sphere header, followed by two-channel interleaved mu-law sample data. The mu-law samples represent the actual digital data transmission from the telephone service provider (MCI), as captured separately for each side of the telephone conversation by the LDC's telephone collection platform. The header also indicates the caller_pin, callee_pin, topic_id, cellular service/handset information and speaker demographic information. The data files are not compressed.

Please examine this example audio file to review a sample of this corpus.


There are no updates available at this time.

Content Copyright

Portions 2004 Trustees of the University of Pennsylvania