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tt0180

join:2010-12-16

4 edits

1 recommendation

Zoom 5341G (4x4) vs Zoom 5341J (8x4)

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5341J
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Newer 5341J
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Newer 5341J
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Older 5341G
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Older 5341G
I recently acquired Zoom's latest revision of their DOCSIS 3 cable modem, the Zoom 5341J, and I thought that I would share my quick initial comparison to Zoom's first revision, the Zoom 5341G.

What I like about the 5341J:

1: The DS and US LED's on the front of the device, will turn from a solid green to a solid blue if two or more channels are bonded on the respective route. For example, if two or more Down Stream channels are bonded, the DS LED will show a solid blue.

2: There is a power switch on the back of the unit which makes it a little easier to power cycle the modem with one hand.

3: The web interface appears to be a bit more responsive.

4: The newer 5341J, for myself, shows a consistent 3-4 dBmV rise in the SNR versus the 5341G. (35/36 on the 5341G vs a consistent 39/40 on the 5341J.)

5: The newer 5341J uses the newer Broadcom chipset and it also comes with a nice passive heat sync which should help with long term stability. (Versus no heat sync on the 5341G)

6: The newer 5341J permits you to reset the device to the factory defaults from within the web interface.

7: The older 5341G runs off of a 6v power supply and the the newer 5341J runs off of a 12v power supply.

8: The newer 5341J is an 8x4 modem versus the 5341G being a 4x4 modem (along with most other DOCSIS 3 modems available at this time). Now, please keep in mind that, just because you have a D3 modem that is bonded to 8 channels on the Down Stream side, it does not mean that you will have a faster connection.

For example: If your modem is provisioned for a 20/4 plan, that is all you will get.

If you are then asking yourself, “What will an 8x4 modem do for me then? It seams as if, unless I have some ridiculously fast plan, an 8x4 modem will not do me any good. I mean, 8 bonded DS channels gives me 343 Mbits vs the 172 Mbits available to me with 4 bonded channels. How can I use all of that when I am on a measly 20/4 plan????”

An 8x4 modem can benefit you and this is why.

Number one, the speeds attainable via Comcasts POWER BOOST feature, should be higher and more consistent. If you are not familiar with their Power Boost feature, it essentially allows you to go beyond your provisioned plan for the first 100 megabytes or so of a file download.

Number two, you need to understand that those rates of 172 Mbits and 343 Mbits, are shared between yourself and everyone else connected to that same piece of copper coming into your home. That piece of coax weaves all throughout your neighborhood and you will be sharing it with hundreds of customers. With 4 bonded downstream channels, it only takes having 8 of your neighbors (of which are on the same 4 channels as yourself) maxing out their “measly” 20/4 connection to slow you down on your 20/4 connection.

Having an 8x4 modem that has bonded to 8 DS channels will ensure a more consistent connection. The chances of 8 random channels being “maxed out” is far less than only 4 random channels being maxed out.

So, you do not need a 100 Mbit plus plan to benefit from an 8x4 modem. Having one will simply ensure that you are capable of getting your subscribed rate more often.

In all, the 5341J appears to be ROCK solid and I would definitely recommend it.

The only thing that I can knock the 5341J for is that, unlike on the older 5341G, you are unable to see the file name of the current configuration file. In my opinion, the benefits that the newer 5341J offers, far outweigh this one minor issue.

I was able to find it for $69.00 with free shipping and I personally feel that, at that price, it is a great deal.

Tony


gar187er
I do this for a living

join:2006-06-24
Dover, DE
kudos:4

1 recommendation

nice review, but a few things,

most all modems lights change when bonded versus single channel

do not trust snr levels from a mode, or signal levels.....levels will vary as much as 6 db between modems/chipsets.....so no way of knowing what is the real level

also your theory of 8 people running their modems to max out your pipe is quite false....seeing as your all assigned different time slots, this will never happen......if all it took were 8 modems downloading at the same time, nodes wouldnt have 500+ devices on them, they would only have 10.....
--
I'm better than you!



EG
The wings of love
Premium
join:2006-11-18
Union, NJ
kudos:9

1 recommendation

reply to tt0180

The poster Ripper See Profile posted in another 5341 thread here;

»New Zoom 5341J 8x4 Modem Installed

that besides not seeing the naming of the config file that there is no error logging in the U.I. either.


tt0180

join:2010-12-16
reply to gar187er

I know that the LED's on the front of most D3 modems do change when a bonded connection has occurred but in this instance, I was only comparing it to the older 5341G which does not. On the 5341G, it shows a solid green regardless and the only way to know is through the web interface.

As far as the SNR is concerned... What is the REAL SNR? I mean, you can take a precisely calibrated piece of lab equipment and measure it but that will not mean anything to the actual device using the signal.

As far as the modem is concerned, all that matters to it is the SNR that it is able to perceive. It is essentially demodulating a signal by accurately measuring a voltage above a noise floor and the greater the difference, more success it will have.

The 5341G, from what I have seen so far, racks up more correctable/uncorrectable words than the 5341J. From an initial perspective, it looks as if the 5341J is able to measure these voltages from the noise floor more accurately.

As far as the 8 other modems are concerned, I probably should have been a bit clearer.

Yes, nodes do have 500+ devices on them but all 500+ aren't Tx/Rx at the same time.

I am not that versed when it comes to the cable side of things but I do know quite a bit when it comes to basic commo theory. I believe that when the CMTS has, lets say, a 10 mb file to send to device number 231, the CMTS looks at all the other devices communicating on the channels between it and device 231 and assigns it a time slot appropriately.

If I remember correctly, the bottom line is that ONE 256 QAM DS channel is only capable of 40ish Megabits per second... Period.

If all 500 devices were each capable of 40 Mbits at the same time, you're looking at 20,000 Mbits on one channel.

Yes, the time is shared.

If 8 of your neighbors connected to the same 4 channels as yourself, were actively maxing out their DS connection at the same time as yourself, you would have an issue.

You would have 4 channels with 40 Mbits a piece. With 9 people actively transmitting, you would each be assigned 1/9th of the available time.

At least, that is my understanding of it.

Tony


tt0180

join:2010-12-16
reply to EG

Click for full size
said by EG:

The poster Ripper See Profile posted in another 5341 thread here;

»New Zoom 5341J 8x4 Modem Installed

that besides not seeing the naming of the config file that there is no error logging in the U.I. either.

Ahh, yes, that is correct. The new 5341J also requires a username and a password to log into the modem status page. The default UN/PW is even on a sticker on the underside of the modem.

In my opinion, the hardware is solid. These minor issues can all change with a software update. If that will ever happen, however, is another story.

tt0180

join:2010-12-16
reply to tt0180

With respect to your standard HFC network in North America, the RF channels on the copper should start at about 100 mhz and go up to 1000 mhz. With 6 mhz per channel, that gives you about 150 channels within that range to share between Video/TV and Data.

Each 6 mhz channel should give you 42.88 Mbits/s (256 QAM - DS)... Period. This will be at the hardware level. Once you get into real world use, you have overhead from other various sources.

There is a difference between a device being connected and a device actively Transmitting/Receiving. A connected device will not be using any of the available bandwidth. When it desires to eventually communicate, it is then assigned a time to transmit.

If three devices are actively receiving data on 1 shared 6 mhz 42.88 Mbit/s channel, they should, in theory, each receive their respective data at 1/3 of the total 42.88 Mbit/s rate or at a maximum of 14.29 Mbits/s each.

This sharing of bandwidth (or more precisely - Time) is known as a Channel Access Method. CDMA, TDMA, FDMA... Etc.

Tony



gar187er
I do this for a living

join:2006-06-24
Dover, DE
kudos:4
reply to tt0180

real snr/MER/BER? you mean measuresd by a calibrated SLM? yea thats what it is.....your moed is calibrated to read it....its too busy doing other things.....hell modems can show bad snr yet the channel is perfectly fine.....

whats perceived should matter at all....what the actual modulation error ratio should....

also measuring the rf from the noise floor has NOTHING to do with codewords....codewords are the actual data in the modulated CW...doesnt matter is your SNR is 32, or 39.....yes under 32 you have issues, but your codewords SHOULD not change inside of the range under the same conditions....if they do, something else is goin on....

and yes thats a good overview of TDMA...and waiting 1/10th of a second isnt that much of a deviation.....its just inherent in the docsis system....people should knwo if they want steady ping/low jitter, go to dsl
--
I'm better than you!


tt0180

join:2010-12-16

Well, I suppose what I am trying to say is this.

Lets say that I have horrible hearing and that my friend Jake has immaculate hearing. (You could even say that I have average hearing and that my friend has superhuman hearing. The point that I am trying to make is that not all Receivers perceive the world in the same way.)

Anyhow, lets move forward with my hearing is bad (I have this constant ringing at times) but I have no problem making out a conversation in a room with a few other people talking.

When it turns into a party however, I cannot make out a thing.

So, you have the real noise floor and then you have the perceived noise floor which is created by the less than perfect receiver.

When it comes to QAM, the modem needs to accurately measure voltages (amplitude) at very specific points in the carrier wave.

Yes, for the most part, once you are above a certain threshold you are good. The precision of the channel tuner will be one of the main factors when it comes to SNR.

Having a higher SNR will help you out when the noise floor jumps due to random outside interference.

Again, however, I do not have a lot of experience with the commercial cable end of things. All of my experience is in SATCOM and general commo.



Ripper
Premium
join:2002-02-07
West Palm Beach, FL
reply to tt0180

Here's link to the chipset »www.broadcom.com/products/Cable/···/BCM3382


KevTech
Premium
join:2002-08-22
Seattle, WA
reply to tt0180

The first (topmost) photo is labeled 5341G but I believe that is the 5341J.


JPnATL

join:2011-11-16
Bethlehem, GA
Reviews:
·Comcast
reply to tt0180

So this is zoom vs zoom on a comcast? Lets simplify it and say which ever one is the latest model that's the one you buy unless u want to buy a modem that has the present capabilities at best with 4 download channels but what if we go 8 then what do ya do? Yeeeeep go buy the latest model.Although I understand your proud of your equipment because my new SB6121 looks very nice........sitting rt beside my SB6120 because they are exactly the same only a different case,if I had to give a slight edge in performance I would have to give it to the SB6120 at this point with both having the same software so it all boils down for buying for the future instead of what u can get by with.Just like routers I have heard that some hung the moon and every dang one I have used are all the same the only difference in some is getting it connected and the wireless section but what matters most in the router remains the same.I think some ppl buy stuff for this big price and they are drunk from the purchase and think its all this and that but the ethernet switch is still the same.The performance for the most part comes from the service provider,if you have a crappy connection then their is not a piece of network equipment in this world you will be impressed with its like putting a new carb on a wore out engine.



Johkal
Cool Cat
Premium,MVM
join:2002-11-13
Happy Valley
kudos:10

2 recommendations

You do realize that the 5341J is an 8 x 4 modem that is priced comparably to current 4 x 4 modems.


tt0180

join:2010-12-16

1 edit
reply to KevTech

Yes, that is correct. The top photo labeled 5341G is incorrect. It is the picture of the 5341J.

My apologies.
Tony

Fixed. ~sorto'


tt0180

join:2010-12-16

1 edit

2 recommendations

reply to JPnATL

It was $69.00 shipped for me and, from my experience, it performs significantly better over the older 5341G.

Furthermore, this is not really a comparison of a Zoom modem vs a Zoom modem. This is a comparison of the original DOCSIS chipset made by Texas Instruments and the newer chipset made by Broadcom.

Lastly, having 8 bonded downstream channels helps with congestion during the more demanding periods throughout the day.

Tony


CplEstesUSMC

join:2005-02-16
Douglasville, GA
reply to gar187er

said by gar187er:

also your theory of 8 people running their modems to max out your pipe is quite false....seeing as your all assigned different time slots, this will never happen......if all it took were 8 modems downloading at the same time, nodes wouldnt have 500+ devices on them, they would only have 10.....

This is incorrect, there are only timslots on the upload, not on the download, the ATDMA timeslots are to avoid the CSMA/CD algorithm that plauges the ping on cable modems. Since there is only one node transmitting on the download and that is the CMTS there is no need for a multiplexing method. Simple memory buffers on the interface will do.

tt0180

join:2010-12-16

Yes, that is correct.


CplEstesUSMC

join:2005-02-16
Douglasville, GA

said by tt0180:

Yes, that is correct.

Your post is confusing, which one is correct? ATDMA on the upload/download or upload only ?


meskinct
Mad Scientist at Work
Premium
join:2002-01-07
Southbury, CT
Reviews:
·Charter
·Comcast

3 recommendations

reply to EG

said by EG:

that besides not seeing the naming of the config file that there is no error logging in the U.I. either.

But it appears that there may be! It's just not a visible link that's clickable in the standard GUI. In my 5341J I go to »192.168.100.1/RgEventLog.asp

and I get a log page

Status
SNMP Event Log
This page displays the contents of the SNMP event log.
Time Priority Description
Wed Dec 21 04:14:17 2011 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=0xxxxxxxxxxxx
Wed Dec 21 04:14:08 2011 Error (4) DHCP RENEW sent - No response for IPv4;CM-MAC=xxxxxxxxxxxxx
Wed Dec 21 04:14:08 2011 Critical (3) DHCP RENEW FAILED - Critical field invalid in response
--
Rich. My Website


EG
The wings of love
Premium
join:2006-11-18
Union, NJ
kudos:9

said by meskinct:

said by EG:

that besides not seeing the naming of the config file that there is no error logging in the U.I. either.

But it appears that there may be! It's just not a visible link that's clickable in the standard GUI. In my 5341J I go to »192.168.100.1/RgEventLog.asp

NICE FIND !!! Thank you !!

Now try to find the config file data please !!!


EG
The wings of love
Premium
join:2006-11-18
Union, NJ
kudos:9
reply to CplEstesUSMC

said by CplEstesUSMC:

said by tt0180:

Yes, that is correct.

Your post is confusing, which one is correct? ATDMA on the upload/download or upload only ?

It's of course the "upload/return path" only.

KevTech
Premium
join:2002-08-22
Seattle, WA
reply to EG

The log does show your CM file name when the modem downloads it but is abbreviated.


EG
The wings of love
Premium
join:2006-11-18
Union, NJ
kudos:9

I don't see that here. Even after a powercycle operation or a full reset back to factory defaults.



Ripper
Premium
join:2002-02-07
West Palm Beach, FL
reply to meskinct

Great find on the log page ! I made it a bookmark.Thanks


KevTech
Premium
join:2002-08-22
Seattle, WA

2 recommendations

reply to EG

What I did was pushed and held the reset button on the back until all lights went out except the power light then I released the button.
Why this worked and reset in the GUI does not I have no idea.



Ripper
Premium
join:2002-02-07
West Palm Beach, FL
Reviews:
·Comcast

Click for full size
said by KevTech:

What I did was pushed and held the reset button on the back until all lights went out except the power light then I released the button.
Why this worked and reset in the GUI does not I have no idea.

Yep that worked,and it stays in the log unlike some modems.


meskinct
Mad Scientist at Work
Premium
join:2002-01-07
Southbury, CT
Reviews:
·Charter
·Comcast

1 edit
reply to tt0180

Glad you all find the log page useful. Why it's missing from the original GUI remains a mystery.

It's a Christmas miracle!

SW Download INIT - Via Config file d11_m_5341j_silver_c01.cm
--
Rich. My Website


KevTech
Premium
join:2002-08-22
Seattle, WA
reply to Ripper

Logs

Maybe push and hold the reset button would work on the surfboard modems as well.



EG
The wings of love
Premium
join:2006-11-18
Union, NJ
kudos:9
reply to KevTech

Re: Zoom 5341G (4x4) vs Zoom 5341J (8x4)

said by KevTech:

What I did was pushed and held the reset button on the back until all lights went out except the power light then I released the button.

That's what I did and no go...
What version of firmware (software) do you guys have ? Here's mine; 5.5.4.4J


Ripper
Premium
join:2002-02-07
West Palm Beach, FL

That's the same firmware I have.


KevTech
Premium
join:2002-08-22
Seattle, WA
reply to EG

Did you make sure to hold the button in until the lights went out?

I have the same firmware.