• Please review our updated Terms and Rules here

USR Sportster power supply voltages

O

Ole Juul

Veteran Member
Joined
Aug 15, 2008
Messages
3,982
Location
Coalmont, BC, Canada
I just came across two classic USR external modems in my stash. I'll probably never use them, but then who knows. At any rate, I want to match up the power supplies for proper archiving. Does anybody know the voltages?

USRobotics Sportster 1200; FCC ID: CJE794PL1200

USRobotics Sportster 14,000 Fax Modem; FCC ID: CJE-0265

I have two USR adaptors and one is 20VAC and the other is 9.2VAC. I had thought that it was the earlier ones that used 20V., but in this case the 9V., one matches in colour with the 1200. I'm amazed that the USR documentation doesn't have voltages. They just say to make sure to use the one that came with it. Are they hoping you will ignore that (as usual) and in this case blow something. Anyway, if somebody has relevant info, I'd be grateful.

PS: I've now looked at some other brands of external modem in my collection and it seems that AC is normal, and not marking voltage is also standard.
 
Thanks Chuck. This is a surprisingly difficult thing to find. None of their manuals state the voltage, and many people on the net are asking and most answers are based on (usually incorrect) assumptions. There are a huge number of Sportsters out there, but according to answers that people have gotten from USR support, both the 28.8 and the 33.3 use the 20V supply as well - at least the models that they had inquired about did.

So, it does look like later ones used 20VAC and the 9.2VAC was earlier ones. There was a 9VAC PS as well, but I won't worry too much about that. It would be nice to find the appropriate voltages for all the model so that people in the future can get these vintage modems going.

I was hoping that someone here had the exact models I listed. If I don't get an answer specifically on the two models, then I think I'll try the 9VAC on both of them, and if it doesn't work on one, then I will try the 20V on that one - and cross my fingers. :)

PS: I'm assuming these modems actually work - that's not a given though.
 
Last edited:
Ole Juul said:
...I was hoping that someone here had the exact models I listed...
Click to expand...

I had my hands on a 14,400 Sportster (same style as more recent 56K models) a few days ago while organizing, it should be easy for me to find again...
 
Chuck(G) said:
20VAC is right for the Sportster 56K as well as the later Couriers.
Click to expand...
You're probably right and I was drunk at the time, but my 56K Sportster Faxmodems (Sportster 325686-03 and USR5686D) have stickers on the back (put there by myself in the distant past) saying 9VAC/1000ma; do you have any info to support 20VAC?

I've got a 14,400 model like OJ is asking about (FCC CJE-0265) but there's no sticker on that one; interestingly, the power supply in that one is pretty similar to the 56K models, a simple bridge and 4 caps, all rated 16V.

The one that is different, with what looks like a switching supply with a transformer, transistor and a main filter rated at 35V, is a 28,800 Sportster FAX modem, and that one has a sticker on the back saying 20VAC/10VA (adaptor # HA-2050).

These voltages do seem to be supported by various forum posts on this subject.

FWIW the 5630B 56K modem uses 9V/1A:
http://www.usr-emea.com/support/s-prod-template.asp?loc=unkg&prod=5630b

Also:
http://www.provantage.com/usrobotics-usr5686-acc~7USB900L.htm

Sorry if I'm just adding to the confusion ;-)
 
Last edited:
It's okay--I went to the pile of modems and pulled out the first wall wart that said "US Robotics" on it and read off the voltage. It could be that this goes to another USR modem, or that there was an engineering revision of the 56K. Microsolutions did that with their Backpack drives, having at least 3 different supplies--14VAC, 9VAC and 5VDC at different times on boxes that look otherwise identical. Material for magic smoke, I guess.

At any rate, the 56K isn't the modem that Ole was asking about, so the question is sort of moot. If I get a chance today, I'll revisit the pile and try to match things up. I noted that I have modems I've forgotten about, such as a Zoom and a Hayes Optima, as well as a few Couriers.
 
Chuck(G) said:
At any rate, the 56K isn't the modem that Ole was asking about
Click to expand...
It was more for the benefit of other folks reading this thread, but I guess using 9V instead of 20 wouldn't cause any harm.

I noticed in passing that among my identical-looking Cardinal modems some use 9VDC while others use 10VAC; fortunately the voltage is listed in the fine print.
 
OK, now I have some real world info. I had two USR adapters and one obviously went with the 1200 because the reflective lettering and yellow plastic colour matched. The other PS was black and is marked 20VDC (reads 24.3 unloaded). According to one list I found, there are indeed some USR modems which require 20V but I don't know which ones. I also discovered that the plug from the 20V one would not fit the modems I tested because, although the barrel was the same size, the pin was thicker. So, here are the (now three) USR Sportster external modems which I tested and found to work with a 9.2 VAC (10.2VAC unloaded) PS.

USR Sportster 1200
USR Sportster 14,400 Fax Modem model CJE-0265
USR Sportster 33600 FAX v3.1

It's a shame that USRobotics doesn't publish a list of model numbers. I've had a hard time IDing them. The only reliable way is to plug them in and type "ati3". If anybody has compiled such a list, it would be a great resource on the net.
 
Some US Robotics sportster use 9V AC and some use 20V AC. This is true for 28k8, 33k6 and 56K. The 9V plug will fit the 20V model, which may work. The 20V plug does not fit the 9V model. I can distinguish the voltage of the modem by looking at it. The 20V connector is a bit larger and more round than the 9V. Of course the 9V connector at the modem is round too, but it looks like it was cut. I wish I had a picture to show you. If you still need help I can take a photo.
 
isopor said:
Some US Robotics sportster use 9V AC and some use 20V AC. This is true for 28k8, 33k6 and 56K. The 9V plug will fit the 20V model, which may work. The 20V plug does not fit the 9V model. I can distinguish the voltage of the modem by looking at it. The 20V connector is a bit larger and more round than the 9V. Of course the 9V connector at the modem is round too, but it looks like it was cut. I wish I had a picture to show you. If you still need help I can take a photo.
Click to expand...

Thanks isopor. I did get my own problem solved, but the important thing on forums like this is to leave a trail of useful information for future searchers. So, if you feel like uploading a picture I'm sure there will be people who will appreciate it.

It is interesting how hard it is to find information on USR modems online. I've spend hours over the years and still haven't come up with a single list of model numbers matched to features. Yes, ATI3 will do the trick, but it would be nice to just have a chart, especially if the modem is not physically accessible.
 
There are a few documents related to USR modems on the Wayback Machine's (archive.org) 3com.com saved pages.

Geez, USR-eaten-by-3Com-eaten-by-HP...US Who?

And, believe it or not, the USR FTP site is still there! Might be a good idea to grab the whole thing, as archive.org doesn't save ftp files.
 
Last edited:
Here's the photo showing the differences between the 9 and 20 V.
I hope it's clear.
P1040664.jpg

I've just found this:
USR Part Number: Voltage: Model Number(s)

1.015.090-B: (Input 120VAC, 60Hz) (Output: 9.2 vac@533mA):
00021800 00021900 00026100 00026400
00026500 00026501 00026502 00026600
00026601 00026700 00026701 00026702
00026800 00026801 00026802 00026805
00026806 00026900 00026901 00026902
00026905 00027800 00092200

1.015.1202-B: (Input 120VAC, 60Hz) (Output: 20vac @750mA):
00027900 00074500 00074600 00074700
00074800 00083900 00083901 00083902
00084100 00114100 00117200 00126500
00126501 00126502

1.015.1286: (Input 120VAC, 60Hz, 16Watts) (Output 9VAC, 1000mA):
00083903 00083905 00083907 00083908
00083909 00084000 00084001 00084002
00084003 00084004 00084005 00126502
00126504 00126505 00178400 00178600
00178602 00178900 00178902 00564100
00568400 00568600 00568602 00568603
00568900 00568902 00568903

1.015.1443-00: (Input: 120v AC, 60 Hz, 21 watts) (Output: 9 volts AC, 1500 mA):
00560500
 
Thanks for the pic isopor. Yes, I've found that list online too. It didn't have the models I was looking for. I wonder where it originated, and if there was more there - but I have a feeling that 3COM probably threw out old info to discourage people from using older stuff.

BTW, it sounds like you have some vintage blood in you. What else can you tell us about old stuff? Do you run any old hardware?
 
Yes I do. I ran two professional BBS during the early 90s here in Brazil. They later became ISPs. Some years later on, my house was full of old computer stuff.
I've been selling those modems now. I'm going to keep some units of the beautiful Courier though. Last month I've upgraded them from 33k6 to 56k. (I had to use a Russian crack).
What a product.

Another interesting piece of equipment is called here LPMaster; If you connect two phones to a pair of wire (that can be miles long) or a leased line, plus one of these, if you pick up a phone the other end will ring, and they'll be ready to talk. We used this for simple modems to communicate (The Courier doesn't need this). I don't know if you have such equipment there:
http://produto.mercadolivre.com.br/...pamento-para-interligar-telefone-lpmaster-_JM
 
isopor said:
Another interesting piece of equipment is called here LPMaster; If you connect two phones to a pair of wire (that can be miles long) or a leased line, plus one of these, if you pick up a phone the other end will ring, and they'll be ready to talk. We used this for simple modems to communicate (The Courier doesn't need this). I don't know if you have such equipment there:
http://produto.mercadolivre.com.br/...pamento-para-interligar-telefone-lpmaster-_JM
Click to expand...

Briefly, I think in the 70s, someone offered a modem where two phone lines could be used to provide nearly twice the speed of a single modem. I can't recall who made it or what it was called. Leased lines were very expensive back then and it was much cheaper to get a couple of conventional POTS lines to improve transfer speed.
 
Chuck(G) said:
Briefly, I think in the 70s, someone offered a modem where two phone lines could be used to provide nearly twice the speed of a single modem. I can't recall who made it or what it was called. Leased lines were very expensive back then and it was much cheaper to get a couple of conventional POTS lines to improve transfer speed.
Click to expand...
On the other hand, if you did have a leased line then you could do the opposite and get the most out of it with a Statistical Multiplexer (StatMux, aka Line Concentrator) which let you make several 'simultaneous' connections over the one line; just scrapped several a few days ago as a matter of fact.
 
MikeS said:
On the other hand, if you did have a leased line then you could do the opposite and get the most out of it with a Statistical Multiplexer (StatMux, aka Line Concentrator) which let you make several 'simultaneous' connections over the one line; just scrapped several a few days ago as a matter of fact.
Click to expand...

Yeah, but if it was the 70s, you probably leased all that gear from Ma Bell anyway. I can remember using that to break a 9600 bps leased line into 1200 bps slices.

If you were serious about getting the most out of a leased line in terms of bandwidth, you'd use one of the synchronous protocols. Async has a per-character overhead, where sync has a simple block overhead, independent of the number of characters in the block.
 
Chuck(G) said:
Leased lines were very expensive back then and it was much cheaper to get a couple of conventional POTS lines to improve transfer speed.
Click to expand...
The leased line price was the main reason we used that equipement. Telco rented leased lines with their 19kbps gears for a fortune. We then contracted a leased voice line, which was basically a mute telephone line pair, jumped properly in the cabinets, originally offered for connecting PBXs. We then plugged in two Courier modems, or two Sportster with a LPMaster. It cost a very small fraction of the price. We were the only one doing that. But the Telco couldn't know that we used it for data. :)

I remember seeing that solution of double lines for double speed in the later 90s, by Microsoft. I didn't know it was an earlier solution.
 
Voltages for various USR modems

Voltages for various USR modems

isopor said:
Here's the photo showing the differences between the 9 and 20 V.
I hope it's clear.
View attachment 7804

I've just found this:
USR Part Number: Voltage: Model Number(s)

1.015.090-B: (Input 120VAC, 60Hz) (Output: 9.2 vac@533mA):
00021800 00021900 00026100 00026400
00026500 00026501 00026502 00026600
00026601 00026700 00026701 00026702
00026800 00026801 00026802 00026805
00026806 00026900 00026901 00026902
00026905 00027800 00092200

1.015.1202-B: (Input 120VAC, 60Hz) (Output: 20vac @750mA):
00027900 00074500 00074600 00074700
00074800 00083900 00083901 00083902
00084100 00114100 00117200 00126500
00126501 00126502

1.015.1286: (Input 120VAC, 60Hz, 16Watts) (Output 9VAC, 1000mA):
00083903 00083905 00083907 00083908
00083909 00084000 00084001 00084002
00084003 00084004 00084005 00126502
00126504 00126505 00178400 00178600
00178602 00178900 00178902 00564100
00568400 00568600 00568602 00568603
00568900 00568902 00568903

1.015.1443-00: (Input: 120v AC, 60 Hz, 21 watts) (Output: 9 volts AC, 1500 mA):
00560500
Click to expand...

For the most part, these are the voltages that the older USR modems required:
9600 Sportster 9VAC (some require a multi-pin mini-DIN connector)
14.4 Sportster 9VAC
28.8 Sportster 20VAC
33.6 Sportster 9VAC
56K Sportster 9VAC

Most of these modems will run on 500mA adapters, but 700mA or more is suggested. Pics of most of these can be seen (and purchased) at http://www.elecshopper.com/ac-adapter.html?limit=all&manufacturer=599 . I will try to get all the corresponding old modems posted soon.

Please note that while most external modems DO require AC to AC adapters, some (most notably Zoom) require 9VDC adapters.
 
You must log in or register to reply here.
Back
Top