keyspan zip-linq retractable cable

[JubyPete]

has anyone played with the zip-linq retractable sync-and-charge cables?

http://www.ziplinq.com/retractable-cable-pda.html

i've seen the cables for ethernet, etc. in our office and they work well, but i haven't seen anyone use a sync-and-charge cable yet. maybe i'm lazy, but the retractable cable is so cluch when packing and traveling...

[Deltrevan]

I have. I like mine really well, but it is somewhat shorter than my "regular" sync & charge cable.

I use it all the time, but I did get a USB extension cable to go with mine.

[JubyPete]

Deltrevan: which ipaq do you have? i just e-mailed them b/c they don't list the 43xx, and for the 41xx they said that it's a power hog...

[Ripper014]

I was looking at them... and I like the concept a lot.. the only problem for me is the maximum length of the cable... 30 inches is just not long enough from my computer which is on the floor to my desktop...

[GSmith]

I love my ziplinq cables for the iPAQ 2215. The 41xx and 43xx series can use more power to charge and sync than a USB port can supply. One report suggests that you can only sync a fully charged 4xxx iPAQ (thus being a "charge then sync" cable). Incidently, this is likely why some "sync and charge" cables come with a switch to "sync or charge". The current
retractable cables do not have this switch.

[JubyPete]

ripper...i'm not sure i would use it as a replacement for my desktop cradle cable. however, if i had a laptop, i would most likely use it as a replacement. i think my primary usage would be for traveling. these days, i have to wrap up: 4 cables if i go on a weekend trip (cell, ipod, ipaq, digicam). good thing i don't have a camcorder? =) again, maybe i'm just being to snooty, but it's a pain wrapping up cables, finding rubber bands or twisties (and not losing them later), and just the bulk that each cable takes up in my bag. i'm still waiting for the ziplinq folks to get back to me if their cable is compatible with my 4350....hopefully!

i'm gonna get their cell phone charger. too bad they don't have a convergence product: have a charger "base" with one power cable (zip-linqed, of course =) out one end, and then plugs on the other side (simple powered usb hub, no?) for 2 to 4 to 6 or x number of devices.

now that i think about it...what's stopping me from buying a bunch of usb retractable cables, and a powered usb hub? that way i don't need multiple outlets or a power strip either. would a powered usb hub give enough power....anyone know?

[GSmith]

The self-powered hub would be my approach if I didn't have an APC TravelPower (which has two USB ports available for charging accessories/necessities).

USB data ports can by specification deliver only 500mA (max) to each connected device. A four-port self-powered hub's power supply should be rated just over 2 Amps (500mA times 4 equals 2 Amps). It's unclear to me if connecting only one or two devices to a 4 port hub would allow you to draw more than 500mA from the ports.

Generally, USB data ports will have a current limiter in them preventing drawing more than 500mA per port, but some hubs may not contain a limiter. I don't know.

Cautions: ziplinq cables are thin and may not be rated for more than the specified 500mA. You may want to contact ziplinq (or competitors boxwave minisync, pocketpctechs Lil'sync) to see if any of their retractable cables can handle more than 500mA. For reference, I would think a 1A rating would be enough.

I'm a fan of ultrasmall. I've seen a belkin USB self-powered 4-port dongle that looks interesting (i.e. small). When shopping for a self-powered hub, look at the size of the power supply - you'll have to carry that, too. In case it's not obvious, avoid "bus-powered" hubs that don't contain a power supply.

[JubyPete]

gsmith: great post. just another quick question.

if each port can only provide 500 mA (whether there are other devices connected or not) and the 4350 is 1560 mA, does that just mean that a USB port would take 3+ times longer than a normal cable? or does that mean that it would only charge up to 500 mA (leaving the other 1060 mA uncharged)? is that what zip linq means by more power hungry?

since i usually recharge overnight, timelyness of recharging is not really an issue (as long as it can be done in 6 hrs or so)

[Ripper014]

Jubypete...

When syncing with my laptop I use my I/R and get away from the use of any cables. I could always sync to my desktop via wifi.. but it would mean inserting my CF Wifi card... and I find just placing it on a cradle is just more convenient...

If I still had my bluetooth dongle I would probably go that route with the desktop...

[GSmith]

Short answer: not quite right.

Charging overnight with the device off should not be a problem (see calculation below that shows just over 3 hours).

By "more power hungry", ziplinq the company is saying that the average amount of current used by the 4350 when charging and syncing is greater than for example the 2215 (i.e. closer to or more than the USB specification)

The 4350 battery capacity 1560mAh. The "h" is important, it stands for "hours". mAh is milliamp hours and represents the capacity of the battery. Without the h it is just mA (milliamps) and represents current draw (my term).

The power specs of the 435x:
Removable/Rechargeable 1560 mAh Lithium-lon user swappable battery. Estimated usage time of fully charged battery up to 17 hours (no wireless, no backlight).

This means that the 4350 at a *maximum time* (no wireless, no backlight) will discharge it's 1560 mAh battery in 17 hours. This represents a *minimum* "on" current draw of 1560/17 = 91mA. Compare that to the 500mA that the USB can supply, which means that when the device is on (but presumably not running anything), there is 500-91 mA left for charging the battery assuming that the power control circuitry in the 435x directs the current in this manner.

It's ok if you don't follow that, but follow this: mAh can be used to calculate charge or discharge times if you know the mA of charging or discharging.

Comparisons of charging cables is done by the amount of current that the charging cable can supply (but ultimately limited by the device charging circuitry). You could compare the 500mA of the USB with the AC adapter "output current" of 2A.

AC Power: AC Input: 100~240 Vac, 50/60 Hz, AC Input current: 0.2 Aac max; Output Voltage: 5Vdc (typical), Output Current: 2A (typical)

Note that 2A is the same as 2000mA.

This means that if there is no current limiter in the device, and the device is off (drawing no power) the AC adaper will charge the 1560mAh battery in 1560/2000 hours, or 46.8 minutes. A USB charger limited to 500mA will charge the battery 4 times slower, or 3.12 hours.

Note that if the device is on, it will take that much longer to charge the device, and it has a greater effect on the USB charger than on the AC adapter.

(if you are reading this far, the following is just extra bonus calculations)

If the device is drawing 100mA, the charge times are:
AC: 1560/(2000-100) = 49.2 minutes; USB: 1560/(500-100) = 3.9 hours

If the device is drawing 300mA, the charge times are:
AC: 1560/(2000-300) = 55.0 minutes; USB: 1560/(500-300) = 7.8 hours.

But again, this is assuming that the USB charger output is limited to 500mA. This is of course the specification of USB, and may be different for chargers with USB output as opposed to USB data ports (Belkin, for example, specification on it's Car charger with USB port is 700mA). Note that all of this is very likely why the iPod is charged over FireWire, as the 6-pin FireWire cable can supply much more current than USB).


Congrats! You got to the end of this message!

[JubyPete]

gsmith....that was an excellent post. i was an engineer in college, but industrial engineering. but i had my share of physics, etc.

so if i'm following correctly, your point about whether or not the hub has a limiter per port still only affects charge time (although at a different factor from how i suggested), right? if there is no limiter, and i only have 1 device plugged into the hub, then all 2000 mA would go to the one device, meaning it would basically be the same as AC power. even at 500 mA, and 3.9 hours (since that's probably the minimum draw at night while i'm sleeping would be fine.

i was also thinking about the a/c adaptor/transformer size when thinking of the hub. heck, i was also thinking maybe that plug could be zip-linqed =)

that makes sense then, why most usb hubs are only 4 port (especially the self-powered). if i can draw on your knowledge for one more tangential triva fact....what do these new 7 port hubs do? if AC current can only supply 2 A (4 port hub, 500 mA each)...does that mean across 7 ports it's only supplying 285.7 mA? maybe it's the kind of thing where 3 are bus-powered (one "reserved" for upstream) and 4 are powered?

[GSmith]

Everything's right except your assumption "if AC current can only supply 2 A (4 port hub, 500 mA each)...". I'm sorry if I implied that. It's coincidence that the iPAQ AC adapter is rated at output 2A and that a 4-port USB hub is rated at 2A. On the 7-port hubs, the power supply would have to be rated at output of 7*500mA = 3.5A for it to meet the specification of "self-powered".

I think you've got it.

[JubyPete]

gsmith...actually, i thought you meant that the outlet provides 2 A =)

thanks again. now if i can only get that outlet in my bathroom to work =)

- plim

[GSmith]

NOW you've opened a can of worms talking about input current! An AC to DC converter (aka AC adapter) "takes in" the same POWER as it outputs (minus the inefficiency of the converter). Power is equal to V*A (not strictly true, but close enough for our purposes here). In the US, input voltage is about 120V. So if it outputs 3.5A at 5V (equals 17.5 Watts of power) then it takes in the same amount of power, and the current equals Amps=Power/Voltage => 17.5/120 = .146 A (which is the same as 146 milliamps)

Summary: Ac input: 146mA @ 120V => DC output 3.5A @ 5v (ignoring inefficiencies in the adaptor). Now you know how to read AC adaptor specifications!

But that's a lesson for another day, I think. You've got the basics.

Congrats!

[dodge_911]

DON'T !!!!

I had one from javoedge (seems like almost every company orders them at the same place :))
It fried the serial connection on my 2215 when i used it with the supplied carcharger and it caused very strange things to happen on-screen, like a faulty tv...
I think it's because it charges and synchs at the same time...

Now, with my non-retractable (switchable) Belkin sync/charge cable, no problems whatsoever...
(mind though, haven't used that one for synching yet, at home i sync over BT or just pop it in it's cradle)