Question

New SB8200 and Xfinity

  • 20 March 2023
  • 5 replies
  • 465 views
J
Badge

I just bought a new SB8200 to replace my DOCSIS 3.0 Modem and I don’t think what the status window is showing me is what I should be seeing. The downstream bonded channels are all QAM256, while the upstream channels are SC-QAM. On the front of the modem, the second light from the top is blue and the third is green.

I was on the phone with Xfinity for almost an hour since they had trouble connecting to and they were finally able to provision it. When I asked them about what I was seeing on the status screen they told me it’s that way since it’s a customer-supplied modem, I don’t buy that answer.

Channel ID Lock Status Modulation Frequency Power SNR/MER Corrected Uncorrectables
29 Locked QAM256 579000000 Hz -4.6 dBmV 40.6 dB 0 0
13 Locked QAM256 477000000 Hz -5.4 dBmV 39.8 dB 0 0
14 Locked QAM256 483000000 Hz -5.1 dBmV 40.0 dB 0 0
15 Locked QAM256 489000000 Hz -4.9 dBmV 40.1 dB 0 0
16 Locked QAM256 495000000 Hz -4.9 dBmV 40.2 dB 0 0
17 Locked QAM256 507000000 Hz -5.0 dBmV 40.2 dB 0 0
18 Locked QAM256 513000000 Hz -4.9 dBmV 40.3 dB 0 0
19 Locked QAM256 519000000 Hz -4.9 dBmV 40.5 dB 0 0
20 Locked QAM256 525000000 Hz -4.8 dBmV 40.5 dB 0 0
21 Locked QAM256 531000000 Hz -4.7 dBmV 40.6 dB 0 0
22 Locked QAM256 537000000 Hz -4.5 dBmV 40.7 dB 0 0
23 Locked QAM256 543000000 Hz -4.6 dBmV 40.7 dB 0 0
24 Locked QAM256 549000000 Hz -4.5 dBmV 40.7 dB 0 0
25 Locked QAM256 555000000 Hz -4.4 dBmV 40.8 dB 0 0
26 Locked QAM256 561000000 Hz -4.3 dBmV 40.8 dB 0 0
27 Locked QAM256 567000000 Hz -4.3 dBmV 40.8 dB 0 0
28 Locked QAM256 573000000 Hz -4.4 dBmV 40.7 dB 0 0
30 Locked QAM256 585000000 Hz -4.8 dBmV 40.6 dB 0 0
31 Locked QAM256 591000000 Hz -4.8 dBmV 40.7 dB 0 0
32 Locked QAM256 597000000 Hz -4.8 dBmV 40.7 dB 0 0
33 Locked QAM256 603000000 Hz -4.6 dBmV 40.6 dB 0 0
34 Locked QAM256 609000000 Hz -5.0 dBmV 40.4 dB 0 0
35 Locked QAM256 615000000 Hz -5.4 dBmV 40.1 dB 0 0
36 Locked QAM256 621000000 Hz -5.3 dBmV 40.3 dB 0 0
37 Locked QAM256 627000000 Hz -5.2 dBmV 40.4 dB 0 0
38 Locked QAM256 633000000 Hz -5.6 dBmV 40.0 dB 0 0
39 Locked QAM256 639000000 Hz -6.2 dBmV 39.6 dB 0 0
40 Locked QAM256 645000000 Hz -6.8 dBmV 39.2 dB 0 0
41 Locked QAM256 651000000 Hz -7.0 dBmV 39.2 dB 0 0
42 Locked QAM256 657000000 Hz -6.4 dBmV 39.7 dB 0 0
43 Locked QAM256 663000000 Hz -5.8 dBmV 39.9 dB 0 0
44 Locked QAM256 669000000 Hz -6.2 dBmV 39.5 dB 0 0
159 Locked Other 678000000 Hz -5.4 dBmV 38.8 dB 1014586555 0

 

 

 
Upstream Bonded Channels
Channel Channel ID Lock Status US Channel Type Frequency Width Power
1 2 Locked SC-QAM Upstream 16400000 Hz 6400000 Hz 46.0 dBmV
2 3 Locked SC-QAM Upstream 22800000 Hz 6400000 Hz 48.0 dBmV
3 4 Locked SC-QAM Upstream 29200000 Hz 6400000 Hz 49.0 dBmV
4 5 Locked SC-QAM Upstream 35600000 Hz 6400000 Hz 49.0 dBmV
5 6 Locked SC-QAM Upstream 40400000 Hz 3200000 Hz 50.0 dBmV

 

 

 

5 replies

plemans
Rank
Userlevel 6
Badge +40

its as its should. 

The 2nd from the top being blue means its connecting with a docsis 3.1 connection for downstream.

The 3rd being green means its only docsis 3.0 on the upstream. Which is normal for xfinity as their upstream is currently not docsis 3.1. 

So thats all appearing as it should

Current setup: Netgear CM3000-->Netgear RBE973S-->2.5gig tp-link switch, Xfinity 1.4gig/240mbps
J
Badge


I understand what the lights mean, but they seem to contradict what I’m seeing on the status page, which is part of my original post. In all fairness, I really don’t know Channel Type and Modulation means but from what I’ve heard from questionably reliable sources, it’s not how it’s supposed to look.

M

Folks, I have a similar issue and I too do not trust the service provider’s evaluation (Spectrum - NNY). Is there a third party or a Arris support number available to verify that my modem is NOT defective (as in, do remote diagnostic)?

 

I have the following on connection page:

Connection

The status listed show the connection state of the cable modem. They are used by your service provider to evaluate the operation of the cable modem.

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 555000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Configuration File OK  
Security Enabled BPI+
DOCSIS Network Access Enabled Allowed  

 

Downstream Bonded Channels
Channel ID Lock Status Modulation Frequency Power SNR/MER Corrected Uncorrectables
33 Locked QAM256 555000000 Hz 0.8 dBmV 42.1 dB 487 161
1 Locked QAM256 351000000 Hz 2.1 dBmV 42.8 dB 343 255
2 Locked QAM256 357000000 Hz 2.3 dBmV 42.9 dB 311 244
3 Locked QAM256 363000000 Hz 2.2 dBmV 42.8 dB 388 229
4 Locked QAM256 369000000 Hz 2.3 dBmV 42.8 dB 434 197
5 Locked QAM256 375000000 Hz 2.5 dBmV 42.8 dB 465 159
6 Locked QAM256 381000000 Hz 2.4 dBmV 42.8 dB 472 256
7 Locked QAM256 387000000 Hz 2.4 dBmV 42.8 dB 402 304
8 Locked QAM256 393000000 Hz 2.5 dBmV 42.8 dB 528 324
9 Locked QAM256 399000000 Hz 2.3 dBmV 42.9 dB 558 338
10 Locked QAM256 405000000 Hz 2.1 dBmV 42.7 dB 631 254
11 Locked QAM256 411000000 Hz 2.3 dBmV 42.7 dB 619 225
12 Locked QAM256 417000000 Hz 2.5 dBmV 42.8 dB 709 362
13 Locked QAM256 423000000 Hz 2.4 dBmV 42.6 dB 597 383
14 Locked QAM256 435000000 Hz 2.6 dBmV 42.7 dB 505 213
15 Locked QAM256 441000000 Hz 2.3 dBmV 42.5 dB 668 251
16 Locked QAM256 447000000 Hz 2.4 dBmV 42.9 dB 654 375
17 Locked QAM256 453000000 Hz 2.6 dBmV 43.0 dB 697 516
18 Locked QAM256 459000000 Hz 2.6 dBmV 42.9 dB 598 262
19 Locked QAM256 465000000 Hz 2.6 dBmV 42.9 dB 430 186
20 Locked QAM256 471000000 Hz 2.6 dBmV 42.9 dB 490 201
21 Locked QAM256 477000000 Hz 2.5 dBmV 42.9 dB 406 283
23 Locked QAM256 489000000 Hz 2.1 dBmV 42.6 dB 273 184
24 Locked QAM256 495000000 Hz 2.0 dBmV 42.6 dB 269 127
25 Locked Other 662000000 Hz 0.9 dBmV 40.5 dB 24570935 3
26 Not Locked QAM256 0 Hz 0.0 dBmV 42.3 dB 313 108
27 Locked QAM256 513000000 Hz 1.6 dBmV 42.3 dB 377 69
28 Locked QAM256 519000000 Hz 1.4 dBmV 42.3 dB 470 115
29 Locked QAM256 525000000 Hz 1.3 dBmV 42.1 dB 484 202
30 Locked QAM256 531000000 Hz 1.1 dBmV 42.0 dB 440 228
31 Locked QAM256 537000000 Hz 1.1 dBmV 41.9 dB 451 221
32 Locked QAM256 543000000 Hz 0.8 dBmV 41.9 dB 399 170

 

 

Upstream Bonded Channels
Channel Channel ID Lock Status US Channel Type Frequency Width Power
1 65 Locked SC-QAM Upstream 17800000 Hz 6400000 Hz 40.0 dBmV
2 66 Locked SC-QAM Upstream 24200000 Hz 6400000 Hz 41.0 dBmV
3 67 Locked SC-QAM Upstream 30600000 Hz 6400000 Hz 41.0 dBmV
4 68 Locked SC-QAM Upstream 37000000 Hz 6400000 Hz 42.0 dBmV

 

 

Current System Time: Fri Mar 24 11:43:37 2023

Channel 22 is missing on mine. Mine is an “Arris Refurb” unit from Amazon. Do they sell those there?

Thanks.

J
Badge

The initial modem I bought was a refurbished modem from Walmart’s website. The paperwork in the package said the warranty was for two years When I thought it was defective I gave Arris a call and after a S/N check they told me it was out of warranty. Fortunately, it was within Walmart’s 30-day return period so I was able to return it and buy a new one off the shelf.

 

I’m planning on calling Arris again to see if they can get into the modem and make the changes Comcast won’t do.

 

M

I too seem to be having problems as Channels 25 and 26 do not look correct to me for Comcast. Channel 25 modulation is set to Other and Channel 26 is Not locked and the Frequency is zero.

Speedtest shows good up and down speeds, but every 3 days or so I get a whole bunch of uncorrectable errors. Resetting the modem zeros all errors except Channel 25 which has correctable errors numbering in the millions and zero uncorrectable errors.

My modem is a refurbished modem bought from Amazon. Below is what I see-

I beginning to think that these refurbished modems are not any good. Someone correct me if I am wrong.

Reply


Terms & ConditionsCookie settings