[ARTERA LETTERHEAD]


EXHIBIT 10(as)
                                                              November 9, 2001

To each of the Investors
identified on Schedule A hereto

Gentlemen:

     In  connection  with the  prior  issuance  and sale by Artera  Group,  Inc.
("Artera") to the investors identified on Schedule A hereto (the "Investors") of
shares of Series A Convertible  Preferred  Stock,  par value $0.01 per share, of
Artera,  identified on Schedule A hereto (the "Preferred  Shares"),  this letter
will confirm our agreement as follows:

     1. In  order  to  permit  NCT  Group,  Inc.  ("NCT")  to  file  one or more
registration  statements  covering  the  resale by the  Investors  of the common
stock,  par value $0.01 per share, of NCT (the "NCT Common Stock"),  issuable by
NCT upon the Investors' exchange of the Preferred Shares, in accordance with the
terms of that certain  Exchange Rights Agreement  (Preferred),  dated as of June
29, 2001, by and among NCT and the Investors,  the Investors hereby  irrevocably
waive their rights to convert the Preferred  Shares into common stock, par value
$0.001 per share, of Artera ("Artera Common Stock").

     2. In  connection  with the  waiver  by the  Investors  of their  rights to
convert the Preferred  Shares into Artera Common Stock, the Investors also waive
those rights granted under the  Certificate  of  Designations,  Preferences  and
Rights of the  Preferred  Shares,  as filed with the  Secretary  of State of the
State of Delaware on February  23,  2001 (the  "Certificate  of  Designations"),
relating  to: (i) the  conversion  of the  Preferred  Shares into Artera  Common
Stock;  (ii) the Investors' rights to force a redemption of the Preferred Shares
pursuant to Section 6 of the  Certificate  of  Designations;  and (iii) Artera's
reservation and delivery of shares of Artera Common Stock.

     3. In  connection  with the  foregoing  paragraphs 1 and 2, (i) any written
agreement(s)  relating to the  Preferred  Shares shall be deemed  amended to the
extent necessary to effectuate the immediately preceding paragraphs and (ii) the
Investors  shall  not be  deemed  to  have  waived  any  other  rights,  accrued
penalties,  damages,  liquidated  damages and interest under the  Certificate of
Designations or any written agreement(s) relating to the Preferred Shares.

     If the above  accurately  sets  forth our  understanding,  please  sign and
execute one copy of this letter agreement.

                                ARTERA GROUP, INC.

                                By:     /s/
                                        Name:
                                        Title:

ACKNOWLEDGED:

NCT GROUP, INC.

By:      /s/
         Name:
         Its:



AGREED AND ACCEPTED:


AMRO INTERNATIONAL, S.A.


By:      /s/
         Name:
         Title:

AUSTOST ANSTALT SCHAAN


By:      /s/
         Name:
         Title:

BALMORE, S.A.


By:      /s/
         Name:
         Title:

THE GROSS FOUNDATION, INC.


By:      /s/
         Name:
         Title:

ICT N.V.


By:      /s/
         Name:
         Title:

LEVAL TRADING, INC.


By:      /s/
         Name:
         Title:

LIBRA FINANCE, S.A.


By:      /s/
         Name:
         Title:

NESHER LTD.


By:      /s/
         Name:
         Title:

TALBIYA B. INVESTMENTS LTD.


By:      /s/
         Name:
         Title:

UNITED SECURITIES SERVICES, INC.


By:      /s/
         Name:
         Title:




                         SCHEDULE A TO LETTER AGREEMENT


INVESTOR                          NUMBER OF           STATED VALUE  CERTIFICATE
                                  SERIES A                          NUMBER
                                  PREFERRED SHARES

AUSTOST ANSTALT SCHAAN            1,077               $1,077,000    P23 and P24
7440 Fuerstentum
Lichtenstein, Landstrasse 163
Fax: 011-431-534532895

BALMORE, S.A.                     1,077               $1,077,000    P21 and P22
P.O. Box 4603
Zurich, Switzerland
Fax: 011-411-201-6262

AMRO INTERNATIONAL, S.A.          471                 $471,000      P25 and P26
C/o Ultra Finanz
Grossmuenster Platz 6
Zurich, Switzerland CH8022
Fax: 011-411-262-5512

THE GROSS FOUNDATION, INC.        70                  $70,000       P31
1660 49th Street
Brooklyn, New York
Fax: 718-851-3511

LEVAL TRADING, INC.               260                 $260,000      P32 and P33
C/o Thierry Ulmann
14 rue du Conseil-General
CH-1205, Geneva, Switzerland
Fax: 011-4122-321-0807

NESHER LTD.                       107                 $107,000      P27 and P28
Ragnall House, 18 Peel Road
Douglas, Isle of Man
1M1 4L2, United Kingdom
Fax: 011-44-1624-661594

TALBIYA B. INVESTMENTS LTD.       116                 $116,000      P29 and P30
Ragnall House, 18 Peel Road
Douglas, Isle of Man
1M1 4L2, United Kingdom
Fax: 011-44-1624-661594

UNITED SECURITIES SERVICES, INC.  21                  $21,000       P35
135 West 50th Street, Suite 1700
New York, New York 10020
Fax: 212-541-4410

ICT N.V.                          77                  $77,000       P36
Antwerp Tower
De Keyserlei 5 Box 59
2018 Antwerp, Belgium
Fax: 011-32-3-233-2680

LIBRA FINANCE, S.A.               1,000               $1,000,000    P3 and P6
P.O. Box 4603
Zurich, Switzerland
Fax: 011-411-201-6262