hi all. i hope this is the appropriate group, i have not used electronics hierarchy in last years.
i have a US Robotics 5686-02. my sister lost the adaptor to it. i am using one from a Best Data modem but i'm only getting 16,800 kbps (undervoltage?).
should i scan using a variable power supply? i've contacted USR, and i hope they right back. by the time i pay for construction of a variable supply, i could buy a brand new modem. i don't have any applicable parts (317? 337?) in my junkbox. please help.
Simply put, meet the voltage requirements and then meet or exceed th aperage requirements at the proper polarity...After that, there is n need for further speculation. If the supply is 9vdc @ 250ma, anythin
9vdc at 250ma or greater will suffice. Your connection sopeed ha nothing to do with the power supply, it is your network that i slowing you down, not your power supply. Make sure that windows i not limiting your bandwidth by setting it for the intended bandwidt manually, this can be done from your modem properties....
Voltage is critical, but if you have more current available than wha
apparently i am using an AC to AC adaptor and i need an AC to DC adaptor. i contacted USR and they told me 9 Volts at 1 amp is fine. i am very lucky i didn't blow my modem out, new ones are $100 (although mine is an old v90).
i think i'll save up for a new v92 or get the proper adaptor from Rat Shack.
USR gave me the part number, and said that there are vendors who carry it.
as far as the speed, this modem was in storage for years. prior to that i got 40 kpbs on most phone lines. i am now getting 16.8 kbps. i checked the port speed and other things. this is the lowest speed i have ever gotten on
56k modem, other than having an x2 / k56flex incompatibility years ago.
i will also check for noise on the phone lines. the other computer / modem hooked to this line gets 40 kbps.
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Not necessarily true.
Most wall-warts have regulation running about 30%, so if you have
one rated for 9V at 1A and you use it with a 250mA load chances are
you'll be hitting the load with about 12V.
The DC adaptor would probably also work - I opened mine when it got fried by lightening and there was a four diode bridge feeding a 5 volt regulator. Put in DC and the thing will probably still work as long as the voltage is high enough to stay in regulation. If there's another voltage used in it (like something for the serial data link) I didn't find it.
Modems modulate the DC level the phone company supplies. The 5 volts just works the electronics of the modem - ultimately that is sent to an audio modulated current shunt across the phone line.
Do you have any software that shows the upload/download traffic graphically in real time? I'm using "DU meter." My USR modem would connect at 5333 and work for a time at full speed then slow down (whole graph drops one level) work for awhile then slow down some more (in steps).
It is supposed to do that when it encounters noise on the line causing missing or corrupt packets - but it is also supposed to recover if the noise isn't there - speed up again. The firmware for the modem was wrong. I downloaded the updated firmware and it works as advertised.
The firmware also makes it a V92 modem. They supply some fancy graphics software on their site - but it is the firmware that matters. Flashing the modem was no problem and unlike a motherboard it is relatively easy to recover if you botch it.
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John makes a very important point. Two other parameters not yet defined are voltage regulation (ie 30%) and ripple voltage. 30% it typically more than most 'regulated' adaptors output. They are used when rest of a power supply is inside the modem. Typically, an AC adaptor that regulates to within 5% should be sufficient and should have low ripple voltage. In a few cases, I encountered devices that required 1% regulation.
Too much ripple voltage would > On 07 Jun 2006 07:53:59 GMT,
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