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From: james@netcom.COM (James Paul)
Newsgroups: comp.dcom.modems
Subject: Re: Why do they insist on power cubes???
Message-ID: <26284@netcom.COM>
Date: 1 Mar 91 06:17:44 GMT
References: <191@raysnec.UUCP> <14@mich-ns.UUCP>
Distribution: usa
Organization: Netcom - Online Communication Services  UNIX System {408 241-9760 guest}
Lines: 55

In article <14@mich-ns.UUCP> tech@.UUCP (Mich. Network Sys. TECH SUPPORT) writes:
>In article <191@raysnec.UUCP> shwake@raysnec.UUCP (Ray Shwake) writes:
>"
>"	What began as an annoyance has become a logistic mess. Some years
>"ago, manufacturers of external modems like Hayes moved their power supplies
>"to external power cubes which fit directly into the power line. A small
>"power lead then fed the small, stylish modem. While some (like Prometheus)
>"kept to the internal power supply, most others followed the move to power
>"cubes.
>"
>"	Lately we procured a slew of Telebit T1000's - a low cost PEP/MNP
>"modem. The unit itself is modest in size, but the external cube is a heavy
>"monster almost the size of the old six-volt batteries, with long, heavy
>"cables out both ends. Specs show the unit only draws 0.2 amps max. The 
>"units will fit nicely onto our computer room shelves, but now what do we
>"do with the transformers???
>"
>"	Given advances in micro-miniaturization - hey, they can fit
>"transformer, electronics, and battery in your rechargeable razor - why do
>"modem users have to suffer so? Perhaps engineering should spend less time
>"on creating yet another protocol and a little more time on product design!
>"
>
>The Telebit power supplies are made by a separate company. Yes, I agree
>that they should have some sort of device with ONE of these "bricks"
>and a "power strip" into which you can plug, say, 8 or 10 modems. In
>the mean time, you could always buy the Rackmount units and pay an extra 
>$1k for the rack unit. ;->  (The modems themselves are cheaper in rackmount
>than the standalone's are).
> 
>John
>
Or, you could simply use another power supply. These "power cubes" are
more commonly known as wall transformers or AC adapters. They usually
consist of a single step-down transformer in the 9 to 12 volt range.
Some rectify the AC to DC, filtering with a single capacitor.

If you have 10 0.2amp modems that run on 12vdc for example, just wire
up a harness with 10 connectors and run the modems off any supply. You
can get power supplies in that range rated at 5 amps or more for $10.
(Or a few $ more at Radio Shack :-) Also, you can pay a few more $ to
get a good regulated supply.

Most wall transformers are cheaply made and don't live long. Many of
them are rated for less power than the device needs. (I have bought
lots of things that draw 600-900ma, but come with a 500ma cube.) I
usually hack off the connector and use another supply. (I have lots
of stuff that's on continously.)

-- 
James L. Paul

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