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SVG2482AC: Cable Signal Levels

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Article Number	000024902

Title	SVG2482AC: Cable Signal Levels

URL Name	SVG2482AC-Cable-Signal-Levels

Summary	SVG2482AC: Cable Signal Levels

Validation Status	Ready for Review

Keywords

RF, signal strength, cable, specs, specifications, set, online, Comcast, Xfinity, Voice, Telephony, triple-play

Question

What are the acceptable cable signal levels for the SVG2482AC Gateway?

Answer

Cable signal levels for all DOCSIS cable modems require to be within the acceptable level for the modem operate properly. The three signal levels that need to be within the acceptable level are Downstream Power, SNR (Signal to Noise Ratio), and Upstream Power. Downstream Power refers to the line signal sent from the cable provider to cable modem. Downstream SNR (Signal to Noise Ratio) refers to the signal being sent in relation to the noise on the line. Upstream Power refers to the line signal from the cable modem to transmit data back to the cable provider. This document describes how to check the three signal levels to be within the acceptable level for the modem operate properly.

Checking Signal Level

Launch a web browser, such as Internet Explorer, Firefox, or Safari. Enter http://10.0.0.1 into the address box, and press the Enter key. The Login page will appear.
On the Login page, enter admin in the Username field.
Enter password in the Password field then click the Login button. The Gateway > At a Glance page will appear.

NOTE: A prompt to change the password appears when the SVG2482AC is using the default password. To change the password click the OK button or click the Cancel button to bypass it.
On the left hand-menu, click the Connection link then click the XFINITY Network link on the sub-menu. The Gateway > Connection > XFINITY Network page will appear.
In the Downstream section, verify Power levels are within the acceptable range of -15 dBmV to +15 dBmV for each downstream channel.
In the Downstream section, identify the Modulation and Power to verify SNR levels are within the acceptable range for each downstream channel.

Downstream Signal To Noise Ratio (SNR)
Modulation Power Acceptable Downstream SNR
64QAM -15 dBmV to 15 dBmV 23.5 dB or greater
256QAM -6 dBmV to 15 dBmv 30 dB or greater
-15 dBmV to -6 dBmV 33 dB or greater

In the Upstream section, identify the Symbolic Rate to verify Upstream Power levels are within the acceptable range.

Upstream Transmit Power Level
Channel	US Channel Type	Symbol Rate	Acceptable Upstream Power Levels
Single	TDMA	1280 Ksym/sec	45 dBmV to 61 dBmV
	ATDMA	2560 Ksym/sec	45 dBmV to 58 dBmV
	ATDMA	5120 Ksym/sec	45 dBmV to 57 dBmV
Two	TDMA	1280 Ksym/sec	45 dBmV to 58 dBmV
	ATDMA	2560 Ksym/sec	45 dBmV to 55 dBmV
	ATDMA	5120 Ksym/sec	45 dBmV to 54 dBmV
Three or more	TDMA	1280 Ksym/sec	45 dBmV to 55 dBmV
	ATDMA	2560 Ksym/sec	45 dBmV to 52 dBmV
	ATDMA	5120 Ksym/sec	45 dBmV to 51 dBmV

Refresh the page at least twice to identify variations in SNR, Downstream Power, and Upstream Power.

NOTE: If the either of the signal levels are outside of the acceptable range, power cycle or factory reset the gateway.
Contact the cable provider to adjust the signal level to the acceptable level range if the signal levels are outside of the acceptable range.

Acceptable Signal Levels

Acceptable Downstream Power Level
-15 dBmV to +15 dBmV
Downstream Signal to Noise Ratio (SNR)
Modulation	Downstream Power		Acceptable Downstream SNR
64QAM	n/a		23.5 dB or greater
256QAM	-6 dBmV to 15 BmV		30 dB or greater
	-15 dBmV to -6 dBmV		33 dB or greater
Upstream Transmit Power Level
Channel	US Channel Type	Symbol Rate	Acceptable Upstream Power Levels
Single (1)	TDMA	1280 Ksym/sec	45 dBmV to 61 dBmV
	ATDMA	2560 Ksym/sec	45 dBmV to 58 dBmV
		5120 Ksym/sec	45 dBmV to 57 dBmV
Two (2)	TDMA	1280 Ksym/sec	45 dBmV to 58 dBmV
	ATDMA	2560 Ksym/sec	45 dBmV to 55 dBmV
		5120 Ksym/sec	45 dBmV to 54 dBmV
Three or more (>=)3	TDMA	1280 Ksym/sec	45 dBmV to 55 dBmV
	ATDMA	2560 Ksym/sec	45 dBmV to 52 dBmV
		5120 Ksym/sec	45 dBmV to 51 dBmV

Chat Answer	https://arris.my.salesforce-sites.com/consumers/articles/knowledge/SVG2482AC-Cable-Signal-Levels

Record Type	General FAQs

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