That's right. Some Zyxel 645 ADSL Modems (bridge) do look alike (same box and model number on the back) but are indeed different in respect with the Alcatel Chipset they're running inside.
Some 645 are also locked (probably a requirement from the ISP) where some others are not - Unlocking a 645 in order to be able to telnet into is pretty much always duoable (from what I've seen) - There is a (Covad) firmware that you can find here in the forums with instructions on how to unlock your 645 if you CANNOT telnet into it --> »Covad + ZyXEL 600 series 645 modem NOT router
In order to telnet into a 645, you should connect your PC directly to the modem (Ethernet) and set the PC IP to something like 192.168.1.5 (the modem is 192.168.1.1).
Also, various 645 come with a configuration that has different password(s) - I know of 3 possible passwords at the momemt ('1234', 'admin' or 'mspgzyx') - please refer to the link included just above for the actual telnet and *unlocking* instructions - you will find the modem ROM (covad2.zip) that unlocks the modem in the link as well. But make sure you really cannot telnet into the modem before FTP'ing a new ROM. Note that you can always FTP on a 645 assuming you know the password to log in (1 of the 3 above).CAUTION
: You should ALWAYS be careful when flashing a new configuration file or firmware onto your modem - it is a risk and you may end-up with a dead modem (paper-weight!)
Now, concerning the various firmware types:
It has been reported that some latest firmware(s) for the 643 (fw AY.4) and 645 (fw EK.4) can increase noise margins on their respective modem model, quite significantly (especially on the download side).
However, NOT all the 645 can be firmware upgraded. It depends on the Alcatel Chipset Version that they run. When you upgrade the firmware ('ras' file) you *also* have to upgrade the config rom with the one that comes with the firmware ('rom-0' file) in the archive and then reset the VPI/VCI (i.e. 0/35 for Covad).
Once you can telnet into the 645 and access the menu then you can find out which alcatel chipset version you're running by entering menu 24.2.1
Here are the 2 possible output you may get:
ZyNOS F/W Version: V2.50(EK.3
) | Aug 31,2001
ADSL Chipset Vendor: Alcatel, Version 3.8.124
ZyNOS F/W Version: V2.50(EK.4
) | 9/19/2002
ADSL Chipset Vendor: Alcatel, Version 3.8.164
ZyNOS S/W Version: V2.50(FF.2
) | 8/22/2002
ADSL Chipset Vendor: Alcatel, Version 3.6.70
The first one (EK.3) should allow you to upgrade to EK.4 version of the firmware which increases noise margins.
If you already have EK.4 (second one) then you don't need to do much as you have the latest and greatest
If you have FF.2 (third one), then you're out of luck as you won't be able to upgrade the firmware on that 645 - I checked with Zyxel and this is the latest indeed and a different Alcatel Chipset revision level (v3.6.xx) than the other one (v3.8.xxx).
You can get the EK.4 firmware and configuration files from here --> »www.zyxel.ru/ftp/filebase.asp?Us ··· nce=3102
(if your 645 is a bridge and not a router one)
So first, get to know the firmware and alcatel chipset revision your 645 is running; then see if you want and can upgrade the firmware and config file on the modem - make sure to measure your downstream and upstream noise margins before and after the upgrade. You can access the 645 documentation and command to run at »www.zyxel.ru/ftp/filebase.asp?Us ··· nce=3105
(there is a zip file which contains info on the modem's commands, etc) as well as a few PDF's.
Hope this helps,
Please let me know (gdm, Bill_MI and others) of anything which I may have said that is wrong and I will fix it in the post (PM me) or add-on to the thread.
--pheebau[text was edited by author 2003-06-17 22:05:37]