                                                  ZyXEL Communications Corp.
                                                     edited by Manfred Recla
                                                               July 25, 1999


        Release Note on ZyXEL's "G1" Modem series (=> U-1496xx)
        Version 6.21  - PUBLIC RELEASE -          July 13, 1999
        =======================================================


1.) filenames:
--------------------------------------------------------------------------
R621.TXT ........... This release notes for U-1496 series firmware v6.21


internal modem card (for PC's long ISA 8-bit slot), max. 19200bps
RM621BP.U24 ......... U1496B+          -> firmware v6.21 for EPROM U.24
RM621BP.U25 ......... U1496B+          -> firmware v6.21 for EPROM U.25


internal modem card (for PC's long ISA 8-bit slot), max. 16800bps
RM621B.U24 .......... U1496B           -> firmware v6.21 for EPROM U.24
RM621B.U25 .......... U1496B           -> firmware v6.21 for EPROM U.25


external modem with LEDs, max. 16800bps
RM621E.U24 .......... U1496E           -> firmware v6.21 for EPROM U.24
RM621E.U25 .......... U1496E           -> firmware v6.21 for EPROM U.25


external modem with LEDs, max. 19200bps
RM621EP.U24 ......... U1496E+          -> firmware v6.21 for EPROM U.24
RM621EP.U25 ......... U1496E+          -> firmware v6.21 for EPROM U.25


modem card for 19" rack system, max. 16800bps
with support for ZyXEL's NMS (Network Management System)
RM621RN.U24 ......... U1496R and RN    -> firmware v6.21 for EPROM U.24
RM621RN.U25 ......... U1496R and RN    -> firmware v6.21 for EPROM U.25


modem card for 19" rack system, max. 19200bps
RM621RNP.U24 ........ U1496R+ and RN+  -> firmware v6.21 for EPROM U.24
RM621RNP.U25 ........ U1496R+ and RN+  -> firmware v6.21 for EPROM U.25


external modem with LCD (without backlight), max.16800bps
RM621S.U24 .......... U1496S           -> firmware v6.21 for EPROM U.24
RM621S.U25 .......... U1496S           -> firmware v6.21 for EPROM U.25


external modem with LCD (with backlight), max. 16800bps, 
with support for ZyXEL's NMS (Network Management System) 
RM621SN.U24 ......... U1496SN          -> firmware v6.21 for EPROM U.24
RM621SN.U25 ......... U1496SN          -> firmware v6.21 for EPROM U.25


external modem with LCD (with backlight), max. 19200bps
RM621SP1.U24 ........ U1496S+          -> firmware v6.21 for EPROM U.24
RM621SP1.U25 ........ U1496S+          -> firmware v6.21 for EPROM U.25


external pocket-size modem, max. 16800bps
RM621CP.U24 ......... U1496P           -> firmware v6.21 for EPROM U.24
RM621CP.U25 ......... U1496P           -> firmware v6.21 for EPROM U.25
-------------------------------------------------------------------------


Solved modem bugs:
==================
1.Leased Line problem:
  In some cases, the link layer may hang.

2.German EG model:
  Can't use tone dialing if country code is other than 237 (Germany).



electronic greetings from Vienna, Austria
Manfred Recla
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