Power Jack in PCMCIA card for USB/IEEE Ports

G

Guest

Guest
Archived from groups: comp.sys.laptops (More info?)

I am looking to buy a PCMCIA card with 2 USB 2.0 ports and 2 IEEE 1394
ports (4 and 6 pins). This PCMCIA card has a provision for a 12V power
jack. What is the need for power input? When should I give input power?
Does all FIREWIRE/USB PCMCIA cards need/has such provision? Please let
me know better pcmcia card for me.

Regards,
Vasanth
 
G

Guest

Guest
Archived from groups: comp.sys.laptops (More info?)

On 15 Jun 2005 20:37:13 -0700, bvasanth123@rediffmail.com wrote:

>I am looking to buy a PCMCIA card with 2 USB 2.0 ports and 2 IEEE 1394
>ports (4 and 6 pins). This PCMCIA card has a provision for a 12V power
>jack. What is the need for power input? When should I give input power?
>Does all FIREWIRE/USB PCMCIA cards need/has such provision? Please let
>me know better pcmcia card for me.


If u have a choice, pick the one with power of course.

What's the need for power input? Mostly for convinience.

A PDA I had was able to recharge though the USB cable. Since I always
travel with both pieces together, I afforded to forgo a separate
charger for the PDA.

A portable DVD drive I had could draw power from the FW port. If I
didn't the 6-pin FW port or cable, then I had to use a separate power
plug for the drive.
 
G

Guest

Guest
Archived from groups: comp.sys.laptops (More info?)

<bvasanth123@rediffmail.com> wrote in message
news:1118893033.374024.320640@g44g2000cwa.googlegroups.com...
> I am looking to buy a PCMCIA card with 2 USB 2.0 ports and 2 IEEE 1394
> ports (4 and 6 pins). This PCMCIA card has a provision for a 12V power
> jack. What is the need for power input? When should I give input power?
> Does all FIREWIRE/USB PCMCIA cards need/has such provision? Please let
> me know better pcmcia card for me.
>

The card (and this is true of hubs as well) needs to be able to supply up to
500mA of current per port. With 4 ports available, that's 2 Amps potential
supply requirement. 2 Amps is rather a large current to pull from a PCMCIA
port, so a separate supply is required to meet the requirements.

The USB and Firewire spec both allow cards (and hubs) of this type to
operate without external supplies, but in these cases the maximum current
per port is limited to 100mA.

I have to say though that a requirement for a 12 Volt input is a little
unusual, 5 volts is more usual as it saves the cost of a voltage regulator.

Ian.
 
G

Guest

Guest
Archived from groups: comp.sys.laptops (More info?)

bvasanth123@rediffmail.com wrote in news:1118893033.374024.320640
@g44g2000cwa.googlegroups.com:

> I am looking to buy a PCMCIA card with 2 USB 2.0 ports and 2 IEEE 1394
> ports (4 and 6 pins). This PCMCIA card has a provision for a 12V power
> jack. What is the need for power input? When should I give input power?
> Does all FIREWIRE/USB PCMCIA cards need/has such provision? Please let
> me know better pcmcia card for me.

Get one that does have the power supply. When I got mine, all seemed to work
fine without using the power supply - that is, until I tried a USB 2.0 1GB
Lexar flash drive in it. So, it did work fine with a USB 1.1 flash drive,
and with my external USB 2.0 DVD drive (with its own power supply), and my
external USB 2.0 hard drive (with its own power supply); but used with
something needing extra power and without its own power supply, the PCMCIA
card needed the extra power source.

--
Tom McCune
http://www.McCune.cc
 
G

Guest

Guest
Archived from groups: comp.sys.laptops (More info?)

"Ye Electrik Fanne Clubbe" <ian.shorrocks@baehisclothessystems.com>
wrote:
>I have to say though that a requirement for a 12 Volt input is a little
>unusual, 5 volts is more usual as it saves the cost of a voltage regulator.

Isn't FireWire power 12V?
 
G

Guest

Guest
Archived from groups: comp.sys.laptops (More info?)

William P. N. Smith wrote:
>Isn't FireWire power 12V?

Google is certainly not my friend today! I've found 30V, 32V, 12V, 5V
all listed as Firewire supply voltages. The Apple iPod supply, which
outputs to a Firewire connector, is listed at 13V.

Since the iPod won't charge on a USB connector, I suspect it's closer
to 12V.
 
G

Guest

Guest
Archived from groups: comp.sys.laptops (More info?)

First, it's probably 5 volts not 12 volts.

Both USB and the large firewire connectors can provide power to
peripherals, but this power is not available from the PC Card slot, so
this jack is needed when the card is to be used with peripherals that
will draw their power from the USB/Firewire port. Otherwise, it's
normally not needed.

Get a card that comes with a switching power supply to provide this power.


bvasanth123@rediffmail.com wrote:
> I am looking to buy a PCMCIA card with 2 USB 2.0 ports and 2 IEEE 1394
> ports (4 and 6 pins). This PCMCIA card has a provision for a 12V power
> jack. What is the need for power input? When should I give input power?
> Does all FIREWIRE/USB PCMCIA cards need/has such provision? Please let
> me know better pcmcia card for me.
>
> Regards,
> Vasanth
>
 
G

Guest

Guest
Archived from groups: comp.sys.laptops (More info?)

<William P. N. Smith> wrote in message
news:r4e3b1hglpn1o3ngtcksrqvj3pea9mt139@4ax.com...
> "Ye Electrik Fanne Clubbe" <ian.shorrocks@baehisclothessystems.com>
> wrote:
> >I have to say though that a requirement for a 12 Volt input is a little
> >unusual, 5 volts is more usual as it saves the cost of a voltage
regulator.
>
> Isn't FireWire power 12V?
>

If you read the IEEE-1394a spec, you will find that although the current
requirements are spelt out, the voltage is left somewhat vague. It lays
down a voltage range. However, on looking into it, it seems that many
firewire cards do ship with 12 volt power supplies, but I am aware of at
least one PCMCIA firewire card (make not to hand) that ships with a 5 volt
supply.