dslreports logo

Cable modems have built-in diagnostics for getting information on the quality of the cable signal coming to the modem. The procedures for accessing these diagnostics vary depending on the brand and model of cable modem you have. If the information below won't get you to these diagnostics, please contact the manufacturer of your cable modem (be it leased or owned). A few modems may have this information in the manual that they came with. For some cable modems, you can access these diagnostics even if the cable modem hasn't obtained block sync.


•The following list is Manufacturer & Model specific. This info. directs you via a link & provides Username / Password where applicable.


Arris CM550A________________ »192.168.100.1 / No username or password required.
Arris CM820A_______________ »192.168.100.1/ ___ No Username or Password required
Arris TG852G (IMS/NCS)_______ Need Info.
Arris TG862G (IMS/NCS)______ »10.0.0.1/ _______ Username: admin / Password: password
Arris TM402G (IMS/NCS)______ »192.168.100.1/ ___ No Username or Password required
Arris TM402P (IMS/NCS)______ »192.168.100.1/ ___ No Username or Password required
Arris TM502G (IMS/NCS)______ »192.168.100.1/ ___ No Username or Password required
Arris TM504G (IMS/NCS/SIP)___ »192.168.100.1/ ___ No Username or Password required
Arris TM508A (NCS/SIP)_______ »192.168.100.1/ ___ No Username or Password required
Arris TM602G (IMS/NCS/SIP)___ »192.168.100.1/ ___ No Username or Password required
Arris TM604G (IMS/NCS/SIP)___ »192.168.100.1/ ___ No Username or Password required
Arris TM608G (NCS/SIP)_______ »192.168.100.1/ ___ No Username or Password required
Arris TM702G (IMS/NCS)______ »192.168.100.1/ ___ No Username or Password required
Arris TM722G (IMS/NCS)______ »192.168.100.1/ ___ No Username or Password required
Arris TM822G (IMS/NCS)______ »192.168.100.1/ ___ No Username or Password required
Arris WBM760A_______________ Need Info.

Cisco DPC3000___ »192.168.100.1/ ___ No Username or Password required
Cisco DPC3008___ »192.168.100.1/ ___ No Username or Password required
Cisco DPC3010___ »192.168.100.1/ ___ No Username or Password required
Cisco DPC3825___ Need Info.
Cisco DPC3939___ »10.0.0.1/ _______ Username: admin / Password: password
Cisco DPC3939B__ »10.1.10.1/ ______ Username: cusadmin / Password: highspeed

D-Link DCM-202___ »192.168.100.1/ __ Username: dlink / Password: dlink
D-Link DCM-202 (Comcast firmware)___»192.168.100.1/ ___ Username: admin / Password: hitron
D-Link DCM-301__ »192.168.100.1/ __ Username: admin / Password :password

Motorola SB5100____ »192.168.100.1/ ___ No Username or Password required
Motorola SB5101____ »192.168.100.1/ ___ No Username or Password required
Motorola SB5101U___ »192.168.100.1/ ___ No Username or Password required
Motorola SB5120____ »192.168.100.1/ ___ No Username or Password required
Motorola SB6121____ »192.168.100.1/ ___ No Username or Password required
Motorola SB6141____ »192.168.100.1/ ___ No Username or Password required
Motorola SB6180____ »192.168.100.1/ ___ No Username or Password required
Motorola SB6183____ »192.168.100.1/ ___ No Username or Password required
Motorola SBG6580___ »192.168.0.1/ _____ Username: admin / Password: motorola
Motorola SBG6700AC_ Need Info.
Motorola SBG6782AC_ »192.168.0.1/ _____ Username: admin / Password: motorola
Motorola SBG901____ »192.168.0.1/ _____ Username: admin / Password: motorola

Netgear CG3000DCR___ »10.1.10.1/ __ Username: cusadmin / Password: highspeed
Netgear CG814CCR-V2_ »192.168.100.1/ ____ No Username or Password required
Netgear CMD31T______ »192.168.100.1/ ____ Username: admin / Password: password
Netgear CM400_______ »192.168.100.1/ ____ Username: admin / Password: password
Netgear CM500_______ Need Info.
Netgear C3000_______ Need Info.
Netgear C3700_______ Need Info.
Netgear C6300_______ Need Info.
Netgear N450________ Need Info.

Scientific-Atlanta DPC2100R2__________ Need Info.
Scientific-Atlanta DPC2203 (IMS/NCS)___ Need Info.
Scientific-Atlanta DPC2203C (IMS/NCS)__ Need Info.
Scientific-Atlanta DPC2203C2 (IMS/NCS)_Need Info.

SMCNetworks SMC8014WG-CCR_____ »192.168.0.1/ _Username: cusadmin / Password: password
SMCNetworks SMCD3G-CCR________ »10.1.10.1/ ___ Username: cusadmin / Password: highspeed
SMCNetworks SMCD3GNV (IMS/NCS)_ »10.0.0.1/ ___ Username: admin / Password: password
SMCNetworks SMCD3CM1604_______ »192.168.100.1/ ___ No Username or Password required

Technicolor TC8305C (IMS)___ »10.0.0.1/ _______ Username: admin / Password: password

Thomson DCM425___________ Need Info.
Thomson DHG535 (IMS/NCS)__ Need Info.
Thomson DHG536 (IMS/NCS)__ »192.168.100.1/ ___ No Username or Password required

Ubee DDM3503____________ »192.168.0.1/ _____ Username: user / Password: user or »192.168.100.1/ ___ Username: admin / Password:cableroot
Ubee DDM3513____________ »192.168.0.1/ _____ Username: user / Password: user or »192.168.100.1/ ___ Username: admin / Password:cableroot
Ubee DVM3203B (IMS/NCS)__ »192.168.100.1/ ___ Username: admin / Password:cableroot
Ubee U10C018____________ »192.168.100.1/ ___ Username: admin / Password:cableroot
Ubee U10C035____________ »192.168.100.1/ ___ Username: user / Password: user

Zoom Telephonics 5241_______ »192.168.100.1/ ___ Username: admin / Password: cable
Zoom Telephonics 5341(G/H)__ »192.168.100.1/ ___ No Username or Password required / Additional Login: »192.168.100.1/rf_index.asp
Zoom Telephonics 5341J______ »192.168.100.1/ ___ Username: admin / Password: password Additional Login: »192.168.100.1/RgEventLog.asp
Zoom Telephonics 5350_______ »192.168.0.1/ _____ Username: admin / Password: admin
Zoom Telephonics 5352_______ »192.168.0.1/ _____ Username: admin / Password: admin
Zoom Telephonics 5363_______ »192.168.0.1/ _____ Username: admin / Password: admin

ZyXEL BRG-35503___________ »192.168.100.1/ __ No Username or Password required


•Thanks to all the posters in this thread who helped with updating this FAQ: »I need your help updating a FAQ !!


• If none of the above methods work, or if your cable modem does not have block sync, you may need to 'force' a connection directly to the modem. This is done by:

1) Set the IP of your ethernet connection to 192.168.100.254

2) Set the Subnet Mask of your ethernet connection to 255.255.255.0

3) Leave the Default Gateway and DNS Servers blank.

4) Reboot your PC.

5) Repeat step "1" as necessary.


• IMPORTANT! Be sure to set your ethernet connection back to DHCP (Obtain IP and DNS automatically) and reboot when you are done checking the diagnostics or you won't be able to access the internet!


• Once you have accessed the diagnostics interface in your browser, you need to know which of these statistics are important and what to watch for if you are having difficulties. See the FAQ: What should my signal levels be? for an interpretation of this information.



*This FAQ is based on user knowledge from a volunteer core of BroadbandReports' members. This FAQ in no way constitutes official information from Comcast or any of its affiliates.





Feedback received on this FAQ entry:
  • Hi, I bought a couple of Netgear CM500 cable modems this past week. To fill in that unit's data, it's the same as the previous several Netgear modems: 192.168.100.1/ ____ Username: admin / Password: password Cheers!

    2015-09-26 20:54:43 (campyguy See Profile)

  • Note to Michael Horowitz. Your appreciation for our FAQ editor's entry here is appreciated. Just so you know, should you add the link to your article, we will follow with a link to your article here -> https://secure.dslreports.com/about sortofageek Comcast HSI Forum Moderator

    2015-02-25 17:45:57 (Sunny See Profile)

  • Thanks for this list. I blogged on the subject on Feb 5th and will add a link to this page. www.computerworld.com/article/2880475/talk-to-your-modem.html Then, since Motorola SURFboards can be maliciously rebooted and/or reset by JavaScript in a web page, I wrote about configuring a router to block access to the modem. www.computerworld.com/article/2887243/using-a-router-to-block-a-modem.html Michael Horowitz

    2015-02-24 19:37:54



Expand got feedback?

by Kylemaul See Profile edited by EG See Profile
last modified: 2015-09-20 12:17:34