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r3l04d · 31-03-09, 06:41 PM

Hey, what is it that restricts the ambit 250 from supporting up to 50meg?, is it the chip? is there a ram module at all? Just looking for a bit of a project
Thanks
warwick

BL4K3Y · 31-03-09, 06:44 PM

It's the area you are in mate, too many peole are getting greedy and forcing the config at the minute so VM are knocking people off. Once it eases off a bit then people will be able to get 50MB. VM are planning to upgrade to 150MB in the next couple of years

.

MickyBe · 31-03-09, 07:15 PM

Quote:

Originally Posted by r3l04d

Hey, what is it that restricts the ambit 250 from supporting up to 50meg?, is it the chip? is there a ram module at all? Just looking for a bit of a project
Thanks
warwick

The ambit 250 uses a broadcom bcm3349 chipset which is DOCSIS 2.0 compatible. The maximum possible speeds using the various revisions of DOCSIS are shown below:

Code:

Direction     Downstream                                      Upstream
Version       DOCSIS                  EuroDOCSIS              Both

1.x           42.88 (38) Mbit/s       55.62 (50) Mbit/s       10.24 (9) Mbit/s
2.0           42.88 (38) Mbit/s       55.62 (50) Mbit/s       30.72 (27) Mbit/s
3.0 4channel  +171.52 (+152) Mbit/s   +222.48 (+200) Mbit/s   +122.88 (+108) Mbit/s
3.0 8channel  +343.04 (+304) Mbit/s   +444.96 (+400) Mbit/s   +122.88 (+108) Mbit/s

As you can see, to get a downstream speed of over 38Mbit, you need to use DOCSIS 3.0 - which the BCM3349 isn't compatible with.

r3l04d · 31-03-09, 07:29 PM

So the new modem im guessing will have to run on docsis 3.0??
Is there an upgrade chip i could use ?

MickyBe · 31-03-09, 07:56 PM

The new virgin modem is indeed DOCSIS 3.

You want to remove the bcm3349 from an ambit 250 and replace it?

I consider myself reasonably skilled at soldering and don't have any trouble removing/replacing the 48 pin TSOP flash chips, but I wouldn't even attempt to replace the BGA broadcom chip.

I think you'd also need to replace the tuner circuit - DOCSIS 3 uses multiple downstream channels to achieve higher throughput whereas DOCSIS 1 only uses a single downstream channel. Notice the throughput of 4 channel DOCSIS 3 is exactly 4 times 38Mbit? Get the connection...

Basicly, you need to replace almost everything in the modem

r3l04d · 31-03-09, 08:14 PM

I get ya mate, thanks for the good explanation. Im good at soldering but the thought crossed my mind.

Cheers bud

31-03-09, 06:41 PM	#1 (permalink)
r3l04d Senior Member Join Date: Jan 2009 Posts: 148 Thanks: 0 Thanked 10 Times in 10 Posts	Ambit modems Hey, what is it that restricts the ambit 250 from supporting up to 50meg?, is it the chip? is there a ram module at all? Just looking for a bit of a project Thanks warwick

31-03-09, 06:44 PM	#2 (permalink)
BL4K3Y Senior Member Join Date: Apr 2008 Location: Colne, Lancashire Posts: 7,004 Thanks: 247 Thanked 1,319 Times in 1,211 Posts	Re: Ambit modems It's the area you are in mate, too many peole are getting greedy and forcing the config at the minute so VM are knocking people off. Once it eases off a bit then people will be able to get 50MB. VM are planning to upgrade to 150MB in the next couple of years .

31-03-09, 07:29 PM	#4 (permalink)
r3l04d Senior Member Join Date: Jan 2009 Posts: 148 Thanks: 0 Thanked 10 Times in 10 Posts	Re: Ambit modems So the new modem im guessing will have to run on docsis 3.0?? Is there an upgrade chip i could use ?

31-03-09, 07:56 PM	#5 (permalink)
MickyBe Junior Member Join Date: Mar 2009 Posts: 20 Thanks: 0 Thanked 2 Times in 2 Posts	Re: Ambit modems The new virgin modem is indeed DOCSIS 3. You want to remove the bcm3349 from an ambit 250 and replace it? I consider myself reasonably skilled at soldering and don't have any trouble removing/replacing the 48 pin TSOP flash chips, but I wouldn't even attempt to replace the BGA broadcom chip. I think you'd also need to replace the tuner circuit - DOCSIS 3 uses multiple downstream channels to achieve higher throughput whereas DOCSIS 1 only uses a single downstream channel. Notice the throughput of 4 channel DOCSIS 3 is exactly 4 times 38Mbit? Get the connection... Basicly, you need to replace almost everything in the modem

31-03-09, 08:14 PM	#6 (permalink)
r3l04d Senior Member Join Date: Jan 2009 Posts: 148 Thanks: 0 Thanked 10 Times in 10 Posts	Re: Ambit modems I get ya mate, thanks for the good explanation. Im good at soldering but the thought crossed my mind. Cheers bud

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