Saturday, November 12, 2005

I went to the computer fair, for the first time in about 8 months, probably more.

It seemed like a really poor turnout. A mate of mine was there, trying to get some 10k RPM SATA drives, and couldn't get anything bigger than 76GB, he gave up.

My mate had asked me to look for ADSL modems. There was only one guy with Linksys stuff, and all he had was a plain ADSL2 modem, and wanted $115 for it. I think that's a bit rich.

I might have to trip into the city again, and get another WAG54G.

I saw the USB hub I bought for almost $20, going for $7, and saw a much nicer powered USB hub, for $20.

I've given up on that wireless bridge I bought a while ago, I think the guy I bought it off is trying to claim the money back from Australia Post, so I need to get a wireless adapter.

I bought a USB one, for $45 or something, a 54Mbit adapter, not too bad.

I also bought a little headset thing, that sits over one ear, with a microphone, for using with skype, or other stuff on my laptop. It's pretty small, so I won't worry about carrying it around.

On my way out, I bought an FM transmitter, it's a "Songbird", which looks like a knockoff of the Belkin one.

It got pretty sad range from the radio, so I expect an aerial longer than 10cm will help.

I opened it up, and I've found the aerial lead, I need to get a length of wire (probaly about 6 feet will do :-) and replace it.

I went back around my mate's place in the afternoon, and continued trying to get IPCop to authenticate using PPPOE with the ADSL modem in bridge mode.

I tried resetting the modem to defaults, and then I set it to boot in "clean" mode, and I could no longer connect to it with ethernet.

I read the manual, and there's a reset button, but it doesn't factory reset the unit, it's just the same as turning it off and on again.

I tried doing it a bunch of times, in case you had to hold it, or press it at a certain time to get it to factory reset, but I couldn't find anyway to do it.

I plugged in the alcatel ADSL modem, that refused to get line sync, which again wouldn't sync, and I came back home, where I could research how to fix the modem.

I wondered if it was something like the NB1300 I've got, that gets screwed up, and needs to be reflashed to get it working again.

I googled for details of fixing modem, and I eventually found this page, detailing problems with Netgear units, that are supposed to use the same chipset.

It had a link to this page, which has lots of excellent information, even though it's in mixed language.

Basically, the gist of it, is that you connect a serial terminal to the modem, watch the boot messages, and then short a couple of pins on the header near the flash chip to cause the checksum of the flash to fail, and the modem falls into TFTP server mode, where you can upload a new firmware.

This sounds quite viable, the main issue though, is that the serial port on the modem is round, and is a 4 pin mini din, ie SVHS socket.

I raided all the cables I have, because I thought I saw one like that the other day, with a round end, and a DB9. I found it, then realised it's a Mac cable, with the 8 or 9 pin round serial port connect for Mac, so that was no good.

Then I remembered about a small analogue modem I've got, that has another similar cable. I found it, but the cable has the full pin set in it too.

This must be a custom cable.

While looking for details of the pinouts of the port, since I think I have a spare SVHS plug hanging around, and I could make up the cable, I found this page, which makes references to the modem, and pinouts, but for a parallel cable, used for reflashing the modem.

It didn't have pinouts for anything on that page either.

I couldn't find the pinouts, and didn't the right cable, so I figured I'd just try shorting the pins at different times after turning on the modem, and see if I could fluke it into TFTP server mode.

That didn't work, I couldn't do it.

I thought about it, and I realised it was going to be pretty simple, since there are only 4 pins, so there's going to be signal gnd, rx and tx, and the combination won't be that hard to find.

I got some short lengths of wire, and pushed them into each pin in the socket, got some aligator clips, and the usb -> serial adapter for my laptop.

I put the clips on pins 2/3/5 in the db9 serial, for rx/tx/gnd (or vice versa, I can never remember which is rx/tx, and it's swapped in the db25).

I then randomly clipped them to the pins on the modem, and started up minicom. I'd found references to the modem serial running at 38400, 8N1, which minicom was configured for.

I turned the modem on, and nothing happened, just the usual thing, of the power LED on the modem coming on, then the diag LED flashing for a second, and going off.

I moved the order of the clips around, and tried again, no luck.

I think it was probably about the 10th or 12th combination that worked. I turned on the modem, and saw something like:

Starting POST - V2.2
SDRAM ... Passed
Loader Checksum ... Passed
Loader (V2.06) Self-Extracting ... Done
Decompressing UMON (V1.62) ... Done/Activated
Flash ATMEL AT45DB161 (Capacity=2112K, PageSize=528, TotalPages=4096)

with more output after that, ending with a normal looking decompress/load/run of the software.

The pinout I ended up with was as follows..

db9/2 -> modem 4
db9/3 -> modem 1
db9/5 -> modem 3

Where the modem pins are labelled clockwise, starting at the bottom (7 oclock position).

I saw something about it running in clean mode, and I wondered if that was anything to do with why the ethernet interface wouldn't come up.

I rebooted the modem, and when it said it was checking APPCODE, I shorted pins 2/3 near the flash chip. Nothing happened, the checksum passed, and the modem booted as normal, with no link still.

I tried a few more times, but had no luck. I wondered if they were the right pins to short. I tried sorting pins 1/2, and that time I caused the checksum to fail, and the modem went into TFTP mode.

It said it was running on, I had it plugged into my laptop, and had detected a 100Mbit link.

I configured my laptop's wired interface to, and I tried TFTPing to it, but it timed out. I looked at the ethernet traffic, and it wasn't responding to ping, or ARP, or anything, which is probably to be expected, since the link isn't up.

I even tried adding the ARP entry manually, but this didn't help.

I rebooted it, and let it boot normally, to the CLI.

I tried to work out if there was a way to factory reset the modem from the command line, or something, but I couldn't find one, and the help was next to useless.

I also tried to work out how to switch the config file the modem was using, to get it to boot in "normal" or "default" mode or something, but I couldn't find that either.

I got a call from my mate, and apparently the alcatel I'd plugged in before I left had line synced.

I went back around to his place, and it did look to be working. I patched the modem to the wireless AP I've got around there, and he was able to browse on his laptop.

We went out for a couple of hours, and then I wasn't interested in clubbing anymore, and I'd left my bike at my mate's place, so I went back there.

The link was still working when I got there, I browsed for a bit, and then I went home.

I continued working on the ADSL modem I had there (even though it was about 2am).

I wondered if there was a problem with getting an ethernet link because I was using a straight through cable.

I looked for a crossover cable, but I don't seem to have one.

I tried connecting the modem to a hub, and a switch, but it wouldn't even autonegotiate the speed with either of those.

I looked for a CLI mode manual for the "Viking" devices, and I found it, here.

It's brilliant, all the commands are defined in there, parameters and all.

I found on page 75, details of the "create ethernet intf" command.

I worked out the command I needed to use was as follows:

create ethernet intf ifname eth-0 ip mask

but it just returned:

Error: Size command not executed

Hmm. I turned on verbose mode ("verbose on").

I looked in the manual again, and on page 646, I found the "size" command documented.

I ran it:


and it returned:

Entry Created
Max PPE Sessions : 1 Max TBG MAC address : 256
Max VCs : 2 Max 1483 VCs : 1
Max PFRaw Rules : 96 Max PFRaw Subrules : 68
Max IPF Rules : 50 Max L2TP Tunnel : 1
Max L2TP Sess Per Tunnel: 1 Max L2TP Peer RWS : 4

At this point I noticed the LAN link LED on the modem was on, sweet.

So I had another go with the original command:

create ethernet intf ifname eth-0 ip mask

This time I got:

Entry Created
Interface : eth-0 MTU : 1500
Interface Sec Type : Private Configured IP Address :
Mask : UseDhcp : False
Physical Interface : - Nat Direction : IN
Configured Duplex : Auto Configured Speed : Auto
Duplex : Full Speed : AutoNeg In Prog
Operational Status : Down Admin Status : Up

After configuring my laptop's wired interface to, I then found I could access the web interface. Hooray!.

For some reason though, the normal login didn't work, and I had to use root/root as the username/password.

I downloaded the latest firmware, from here, and then I extracted it, and loaded it through the web interface.

The unit sat there for a while, and in minicom I saw:


At which point it rebooted, and I watched the serial output:

Starting POST - V2.2
SDRAM ... Passed
Loader Checksum ... Passed
Loader (V2.06) Self-Extracting ... Done
Decompressing UMON (V1.62) ... Done/Activated
Flash ATMEL AT45DB161 (Capacity=2112K, PageSize=528, TotalPages=4096)
First time boot up, verifying flash device checksums ...
CFG1: 49632 : Checksum Passed (00000323) ...
CFG2: 49632 : Checksum Passed (000002F8) ...
ALRM: 8448 : Checksum Passed (000002F6) ...
DHCP: 66000 : Checksum Passed (00000356) ...
FACT: 16384 : Checksum Passed (000894EC) ...
MANU: 4096 : Checksum Passed (00004A85) ...
BOOT: 4096 : Checksum Passed (3F404B89) ...
LOAD: 84480 : Checksum Passed (78EAD288) ...
FILE: 259776 : Checksum Passed (01FA8C2D) ...
DSLC: 77616 : Checksum Passed (11C384C7) ...
APPC: 1502160 : Checksum Passed (90BBF06F) ...


Decompressing "TEAppl.gsz" (1435033->3720144) ... Done
Text Segment Size = 3352096 bytes
Data Segment Size = 368048 bytes
Bss Segment Size = 960560 bytes
System Stack Size = 16536 bytes
HISR Stack Size = 16536 bytes
NetBuffer Pool Size= 712224 bytes
System Memory Size = 2160944 bytes
Start of DSPText = 207c0800 bytes
Decompressing "TEMod.gsz" (64414->152440) ... Done
Decompressing "TEDSL.gsz" (76393->166740) ... Done
File System Memory Size = 389120 bytes
UnTar File System \...\...\..\\.....\\\..\......................\.\..\..\......e
Normal Execution Mode
CfgInit: System Coming up from Default Configuration
Welcome to Viking
GlobespanVirata Inc., Software Release VIK-2.1.040827a1
Copyright (c) 2001-2003 by GlobespanVirata, Inc.
Thu Jan 01 00:00:03 1970 : STATUS ALARM : System Up

Which looked a lot more promising, because there were more files going through, and this time the LAN link was on, and the DSL LED was flashing.

The settings had changed back to the default, and the username/password were back to the normal admin/admin.

It looks like it's back working again.

Since the chipset is the same as used in the Netgear DM602, and I'd read a reference to someone loading the RTA firmware into a DM602, I wondered if I could do it the other way.

I went to look for a DM602 firmware, but on the Netgear support page, there are only 2 firmwares. The first says "not for Australia or Germany", and the second one says "for Germany". Great.

I continued flicking through the CLI mode manual, and I read the "quick reference" at the back.

It seems the "reboot" commands takes params, of the config to boot with.

Argh, it seems that all I had to do was "reboot default", to get it fixed. I tested this, I did a "reboot clean", and it booted with no ethernet link.

I did "reboot default", and it came back up, with ethernet link, and ready to go.


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