How to solve random disconnects to internet of E220 and E170 USB HSDPA modem sticks

[bluetooth]

E220 & E170 :





This thread refers to the 'randomly' disconnects of USB broadband modems as E170, E220. The disconnections are like a physical removal of the modem from the USB port. This problem is caused by a h/w reason on the USB power supply, so the solution is an external hardware patch.

Note that I am a user of an E170 modem which is my sole internet connection for business and personal use. I signed a contract with a local mobile broadband provider, they gave me the E170 and ... the problems started!

You can read the full story (which is similar to those others) at my posts:
http://forum.huawei.com/jive4/thread...hreadID=323238
http://forum.huawei.com/jive4/thread...hreadID=321295

Finally I have my problem SOLVED with an external electronic 'patch'. After this fix, I am fully satisfied with my modem and believe that this is a good product. I can be 'always connected browsing or downloading for hours with speeds up to 4Mbits/s (download)' using a small 'patched' cable or a 5 meters 'patched' USB extension cable (not repeater or USB hub). I did not change any driver, application s/w or the modem's firmware.

Recently I contact another user of the forum.huawei.com with a similar h/w disconnecting problem on an E220 modem and we SOLVE it:
http://forum.huawei.com/jive4/thread...hreadID=323536

This h/w patch is to add some capacitors on the USB power line, 'filtering and reserving' DC voltage for the 3G transmitter preventing the digital disconnection from the USB port. This patch must be done by a technician because we don't want to 'short circuit' any cable!

Of course more typical and preferable for the customer is to have this fix at 'no cost' from the PC or the MODEM manufacturer because it is an extreme incompatibility issue at the USB interface. Two months after solving the problem I found an article for electronics engineers (Huawei designers may have read it) with the conclusion ... don't forget the capacitor! Read it at:
http://www.epn-online.com/page/new58...t-passive.html

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CONCLUSION (from my point of view and for my own case)

Problem is: reset or 'brown out state' of the modem

Caused by: USB power ripple/spikes when modem transmits a lot of data, or at high power (other possible reason: a USB connector malfunction like tremble, crack, dirt etc.)

H/W Solution by the user: contact an electronics technician to add capacitors externally (on a patched cable) 'filtering' the ripple spikes (first check and clean the USB connectors)

H/W Solution by the PC manufacturer: Do better design on the USB port to supply a 'good & steady' power for new advanced USB peripherals (as USB mobile broadband modems)

H/W Solution by Huawei: Add decoupling capacitors or split the power lines of the CPU, USB I/O and GSM/3G circuits to prevent resets and brown outs at difficult (for the circuit) situations.

S/W Solution at firmware: Sorry NOT available, ... or possibly a new firmware could 'amplitude modulate' the RF-TX signal to smooth the rise and fall of the RF PWR OUT at every data burst (true artificial intelligence), or change the threshold of the reset and brown out detect circuits to lower levels which may degrade the total performance of the circuit.

S/W Solution at driver: Sorry NOT good, ... or a new s/w driver could see the disconnects and try to reconnect and if not succeed would restart the computer, etc. I am not joking. Programmers are trying to use E220 for a 'reliable' application:
http://ubuntuforums.org/showthread.php?t=914024

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SERIOUSLY the above could solve at least the following threads (which are carefully determined as 'the same problem'):

SOLVED AT:
- E220 disconnecting
. http://forum.huawei.com/jive4/thread...hreadID=323536

Other case SOLVED by a 'replacement' modem!
- E172 disconnects - massive stability problems
. http://forum.huawei.com/jive4/thread...hreadID=321438

MAY SOLVE:
- E220 looses power?
. http://forum.huawei.com/jive4/thread...hreadID=319534

- E220: the connection aborts unregularily
. http://forum.huawei.com/jive4/thread...hreadID=322459

- E220 Mac woes...
. http://forum.huawei.com/jive4/thread...hreadID=322248

- E170 constantly crashing
. http://forum.huawei.com/jive4/thread...hreadID=321295

- E169 Strange connection drops in Vista
. http://forum.huawei.com/jive4/thread...hreadID=323238

- mobile broadband usb device disconnects
. http://forum.huawei.com/jive4/thread...hreadID=323555

POSSIBLY SOLVES:
- E 172 crash problem on mac os x 10.5.1
. http://forum.huawei.com/jive4/thread...hreadID=322460

- E220 disconnects all the time (post of user 'Prosessor')
. http://forum.huawei.com/jive4/thread...hreadID=321470