Search the FAQ Archives

3 - A - B - C - D - E - F - G - H - I - J - K - L - M
N - O - P - Q - R - S - T - U - V - W - X - Y - Z
faqs.org - Internet FAQ Archives

ZyXEL modem FAQ List v4.2, Nov 20 1995, Part 3 of 5 [Technical FAQs]
Section - T.20B When will better quality speech at higher encoding rates be available?

( Part1 - Part2 - Part3 - Part4 - Part5 - Single Page )
[ Usenet FAQs | Web FAQs | Documents | RFC Index | Forum ]


Top Document: ZyXEL modem FAQ List v4.2, Nov 20 1995, Part 3 of 5 [Technical FAQs]
Previous Document: T.20A How does the voice quality compare versus the Rockwell chipset?
Next Document: T.21 Can a voice call be detected by the modem?
See reader questions & answers on this topic! - Help others by sharing your knowledge
--------------------------------------------------------------------------------

4-bit ADPCM was introduced in 07-05-1994, with v6.13 of the ZyXEL ROMs.  The
increased number of bits improves the voice quality noticeably.

Brent Mosbrook (brentm@zyxel.com) [ZyXEL USA] adds:
"Currently, the sample rate is 9600 samples/second.  3-bit ADPCM requires 
the DTE speed to be 38.4K."

The new 4-bit ADPCM requires a 57,600 DTE speed.

Question Q.10 mentions that there will be a faster DTE rate in the next
generation of modems.  This raises the possibility that even higher
encoding rates may arise in the future.


User Contributions:

Comment about this article, ask questions, or add new information about this topic:

CAPTCHA




Top Document: ZyXEL modem FAQ List v4.2, Nov 20 1995, Part 3 of 5 [Technical FAQs]
Previous Document: T.20A How does the voice quality compare versus the Rockwell chipset?
Next Document: T.21 Can a voice call be detected by the modem?

Part1 - Part2 - Part3 - Part4 - Part5 - Single Page

[ Usenet FAQs | Web FAQs | Documents | RFC Index ]

Send corrections/additions to the FAQ Maintainer:
rwong@direct.ca (Robert Wong Jr.)





Last Update March 27 2014 @ 02:11 PM