Basic Internet Connectivity And Modem Help

[PeteC2]

I currently have voice/internet running through a Thompson (D2) eMTA and a Cisco DPC 3008 (D3) modem.  So far so good, I really have no complaint about speed or consistency...but...my signal strengths are very marginal (upstream varies between 49.0 to 50.5, downstream varies between -11 to -14 with snr 36 - 37 on 4 channels)

Comcast is willing to send me a D3 eMTA which would allow me to knock off a split (it is currently split 3 ways on a balanced splitter - tv/eMTA/internet modem), using a 2-way splitter should give me some signal improvement.

I am in an apartment, and my phone and internet originate in one location, so there is no other advantage to having 2 modems.

Does this make sense, or should I be leaving well enough alone?  I can't help but think that this marginal signal will eventually cause issues.

[i-am-nerdburg · Accepted solution]

You're not seeing any advantage with the two-modem set up over a single eMTA and your signal would improve significantly w/o the splitter. It would probably be best to rework your set up so you only have a single unit. Since it's a telephony modem the signal levels are a little more important, particularly if you rely on it for emergency communication.

[PeteC2]

Thanks for such a prompt reply!  I was heavily leaning that way, but just wasn't sure if I was being too "picky" since my current set up does work well...so far!  (The key words being so far!).

Duh!  I should have asked Comcast...any idea which D3 eMTA they will send?  Hopefully not a gateway, as I have a good router and network set up (I have little faith/use for gateways)

BTW, are all D3 eMTA/modems IPv6 capable?  Not obsessed about it, just curious...

[i-am-nerdburg]

Well, that might be a little sticky. Many systems will require that the eMTA be professionally installed (even if it's just a swap) for liability issues related to 911. However, many systems seem to be allowing customers to swap eMTAs. I don't know if there is an official policy one way or another. If I had my choice I'd take an ARRIS 7 series, but Comcast will send you whatever is on hand.

And yes, IPv6 is a DOCSIS 3 specification.

[aptos100]

Comcast sent me a eMTA and allowed me to swap it out without a problem.

I got an Arris 722G

Anything could show up however. Comcast told me they were going to send me a 702G and I got a 722G. Better eMTA to my advtange so i'm not complaning.

Comcast did tell you there is a 10$ shipping fee right?

[i-am-nerdburg]

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aptos100 wrote:

Comcast sent me a eMTA and allowed me to swap it out without a problem.

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Sweet! Thanks for the input. I can't really think of any legitimate reason why customers couldn't do this, so i hope Comcast is relaxing that policy across the board. DId they have you do something with e911? Or was it just a simple 10 minute swap?

[PeteC2]

When I was on the phone with Comcast they made it sound like it was no big deal just to send me one...and apparently one is on the way, along with a return box to sent the old eMTA and Cisco modems back to them.

[PeteC2]

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aptos100 wrote:

Comcast sent me a eMTA and allowed me to swap it out without a problem.

I got an Arris 722G

Anything could show up however. Comcast told me they were going to send me a 702G and I got a 722G. Better eMTA to my advtange so i'm not complaning.

Comcast did tell you there is a 10$ shipping fee right?

Yep, however, with no prompting on my part, they waived the shipping fee (I would have paid it)

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[PeteC2]

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i-am-nerdburg wrote:

Well, that might be a little sticky. Many systems will require that the eMTA be professionally installed (even if it's just a swap) for liability issues related to 911. However, many systems seem to be allowing customers to swap eMTAs. I don't know if there is an official policy one way or another. If I had my choice I'd take an ARRIS 7 series, but Comcast will send you whatever is on hand.

And yes, IPv6 is a DOCSIS 3 specification.

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Actually, I should have mentioned...my initial install of the eMTA was a self-install in the first place, so no surprise that I'd self-install the replacement.  I did have to do that 911 verification process that they now do over the phone...and they said that they could not send an eMTA without doing that...so I suspect that this fullfills the legal requirements concerning 911.

[i-am-nerdburg]

Thanks for the info guys, I appreciate it. Let us know how it goes.

[PeteC2]

Okay, I received the eMTA today from Comcast, an Arris TM 722G (big suckers, aren't they!).  I swapped out the old eMTA as well as the D3 Cisco modem, dropped a splitter, and installed the new eMTA.  Since my cell phone coverage is so spotty at the house (exactly why I keep a "landline"), instead of calling Comcast to activate, I went through the on-line chat (when activating a new comcast device, you have limited connectivity, but do get on-line connection to a tech).

It took a little longer that way, but no problems and after re-engaging the router to recognize the new modem, everything is up and running again.  As I expected, my signal is certainly better (though still not ideal) and frankly, I am happier with one less modem in the equation.

They sent me a return UPS label, I'll box up the old modems, send 'em back and that should be it.

[i-am-nerdburg]

Good deal! And thanks again for the update, we'll be sure to pass it along in the future.

[dsanbo]

pete....

To be safe......Have CC give you a PRINTED RECEIPT for the returned equipment.....

Might want to keep a printout of the UPS Tracking info, too (when the package arrives at its destination)....

Just want to CYA......!

[PeteC2]

Would I be better off physically returning the modems to my local Comcast center?  We do have on about 15 minutes away...hate all that standing in line though...

[PeteC2]

As a closing note:  After installing the TM 7229 to replace the older D2 eMTA & D3 internet modem, my signal improved somewhat, better, but not great. I still had downstream levels of -9 to -11.5 and upstream levels at 48.0 

I traced my cable through the apartment and found an access panel where there was a 3 way splitter (cable goes to the main living area, and each of 2 bedrooms).  It was a quality splitter, but not balanced, a typical -7db, -7db, -3.5db.  So, I switched lines around, having the line that comes to my eMTA now attached to the -3.5db connector.

As soon as I did this, my signal changed to this:

Status

• Status
• HW/FW Versions
• Event Log
• CM State
• Advanced

RF Parameters

Downstream

	DCID	Freq	Power	SNR	Modulation	Octets	Correcteds	Uncorrectables
Downstream 1	199	741.00 MHz	-8.48 dBmV	36.39 dB	256QAM	2023652	0	0
Downstream 2	197	729.00 MHz	-7.66 dBmV	36.61 dB	256QAM	1001439	0	0
Downstream 3	198	735.00 MHz	-7.96 dBmV	36.84 dB	256QAM	1337313	0	0
Downstream 4	200	747.00 MHz	-8.44 dBmV	36.61 dB	256QAM	1409522	1	0

Reset FEC Counters

Upstream

	UCID	Freq	Power	Channel Type	Symbol Rate	Modulation
Upstream 1	3	30.00 MHz	43.75 dBmV	DOCSIS2.0 (ATDMA)	5120 kSym/s	64QAM

Status

System Uptime:	0 d: 18 h: 55  m
Computers Detected:	staticCPE(1), dynamicCPE(1)
CM Status:	Telephony-Reg Complete
Time and Date:	Thu 2012-04-26 12:40:15

     Interface Parameters

Interface Name	Provisioned	State	Speed (Mbps)	MAC address
LAN	Enabled	Up	1000(Full)	00:1D:CF:7A:05:30
CABLE	Enabled	Up	-----	00:1D:CF:7A:05:31
MTA	Pass	Up	-----	00:1D:CF:7A:05:32

© Copyright 2012, ARRIS Group, Inc., All rights reserved.

Far better than the -11 to -14 down and 49.0 to 51.0 up that I started with.