02
Jun
14

Inside a Netcomm Webmaster Modem

Today I’ve taken some photos of my most modern dial-up modem, the Netcomm Webmaster v90. I bought it back in 2003 as I was still using dial-up at the time. Many modems of the time were either software modems or host controlled modems, usually installed as an expansion card or external USB device. They were cheaper, but would usually not work as well as the complete modems did. I sought out this particular modem because it is a RS-232 external modem supporting the Hayes command set, these were generally more compatible and reliable. In particular if you ran Linux in those days as it was impossible to get HSF or HCF modems working with it.

Netcomm Webmaster modem

Netcomm Webmaster modem

Here is the modem itself (with the top of its manual). It doesn’t have lots of indicator LEDs like earlier modems, it just has some for indicating the link status to the remote machine. Older modems had many more to show the status of the serial line in addition to the link status. I liked the blinky lights on the older devices but this is certainly nicer and simpler to look at.

Logic Board

Logic Board

The main logic board couldn’t look more different to it’s older counterparts. This one is made almost exclusively with surface mount technology, except where necessary. It doesn’t use a Rockwell or Conexant chipset which used to be very common. It doesn’t seem to have a line transformer preferring a solid state solution instead. It does seem to have a number of protection devices that were uncommon on older style modems and even HSF and HCF devices. Interestingly there appears to be a rectifier chip in both the power section and modem front end. Not being an electrical engineer I couldn’t say why.

By checking out the main chips data sheet, I figured that the Hynix chip is a RS-232 interface buffer and that the power supply section may include a voltage converter to create the line voltages required for RS-232. This may explain the rectifier chip on the left side of the board, it may be the tail end of a switch mode converter. The labeled chip is almost certainly the flash chip containing the firmware. The main chip requires an external ADC/DAC so some of the smaller chips around the front end are likely to be these devices.

Modem-on-a-chip

Modem-on-a-chip

Here’s a close-up of the main chip, not much to say about it!

What I find the most interesting is how different the more modern modem is compared to a much earlier one such as the Bit Blitzer. The biggest difference seems to be the front end using solid state circuitry instead of a line transformer and relay or solid state switch. I’m not sure, but I suspect much of it is filtering to improve to signal quality and data rate. Whatever they did this device outperformed the HCF modem I was using before by a wide margin.

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2 Responses to “Inside a Netcomm Webmaster Modem”


  1. 1 goughlui
    June 2, 2014 at 3:10 pm

    Very interesting. I’ve had several pages of modems, and had a stack of chipsets but *never* have I seen an IC+ chipset modem. IC+ is a fairly late company that specializes in low cost single-chip system products such as Ethernet switches. All of the Banksia/Netcomm I’ve seen thus far are Rockwells – so this was a surprise to me! (e.g. http://goughlui.com/?p=462, http://goughlui.com/?p=474, http://goughlui.com/?p=4525 and http://goughlui.com/?p=637)

    I wonder how the DIL phase sounds on this modem. I know the software Modios, Lucent WinModem, Agere SoftModem, Ambient/Intel, TI and Conexant/Rockwell modems all sound slightly different doing V.90.

    Rather unusually, it seems it could have been a voice modem too, but they just never fitted the appropriate parts for the external speaker and mic – the outer shell is reminiscient of the Netcomm NB1300 ADSL modem.

    • June 2, 2014 at 3:33 pm

      Thanks for the comment 🙂

      I hadn’t heard of IC+ before looking inside this device so it was quite the surprise to me as well. I don’t have the gear to record the handshake sound for it, but I don’t remember it doing anything unusual. Then again most of the time I couldn’t get the full 56K speed and I may not have heard the difference on the tinny little speaker.

      From what I remember this one will do faxes, but I never used that feature as I used it exclusively for dial-up internet.

      I think I remember the ADSL modem you mentioned, I think the main difference was that it was blue instead. It didn’t have any other remarkable properties that I remember. I quite liked looking at your modem collection, that’s where I noticed the differences in the front ends compared to this one.

      Cheers
      Sparcie


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