Visitor
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Mid-split active on my node but S33 logs diplexer change as Ignored - what upload am I provisioned for?
I am on the Gigabit + Streaming plan in Boulder, CO 80302. I own my modem, an ARRIS S33 hardware V1.0, firmware TB01.03.001.10_012022_212.S3.
Comcast replaced the amplifier at my pedestal on August 25. It is a CommScope STARLINE FDX line extender, part FDX-LE-XX-XFX, manufactured 2026-05-05.
Since that work, my modem event log shows the CMTS sending diplexer mode change instructions that my modem is refusing:
CMSTATUS:US_Diplexer_Mode_Change_Ignored:TLV-21.1, 85MHz.
CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
The only mode it accepts is 5-42 MHz. My upstream bonded channels are four SC-QAM at 16.4, 22.8, 29.2 and 35.6 MHz, with no OFDMA channel. My node appears to be mid-split enabled and my S33 is not, since the S33 is not on the Next Gen Speed Tier list.
Two questions:
1. What upload speed is my account currently provisioned for on this plan?
2. If I install a Next Gen Speed Tier modem, specifically a Hitron CODA56, will my provisioned upload increase on this same plan at this same price? What speed would it be?
I would also like a signal quality review. My downstream runs -6 to -8 dBmV, the OFDM PLC channel at 957 MHz is -13 dBmV with 38 dB SNR, and I have over one million uncorrectable codewords on several channels across two days of uptime. Upstream transmit is 51.8 dBmV on all four channels.
I am happy to provide my account number and service address by direct message.
XfinityCliff
Official Employee
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560 Messages
22 hours ago
Thank you, @user_y5pfod, for providing such detailed modem and signal information for us here on our Xfinity Community forums!
I can understand wanting clarity after the recent network work. The ARRIS S33 is a DOCSIS 3.1 modem, but it is not currently certified for Xfinity’s enhanced upload speeds, which explains why it remains in the 5–42 MHz upstream mode.
The Hitron CODA56 is certified for enhanced speeds and can use the expanded upstream spectrum when both the address and plan are eligible. Typically, enhanced-market uploads range from 75–200 Mbps, but your exact provisioning and whether changing modems would increase it at the same price require an account-level review.
Your 51.8 dBmV upstream transmit levels, low OFDM PLC level, and rapidly accumulating uncorrectable codewords also warrant a closer signal review.
Please send us a Direct Message* with your full name and complete service address, and we’ll check the provisioned upload speed, CODA56 eligibility, bootfile, and connection health.
How to Send Us a Direct Message*:
(*Note: Never send a direct message to us unless requested by us.)
Click Here For an example of how to send us a Direct Message.
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EG
Expert
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120.4K Messages
2 hours ago
@user_y5pfod
The downstream power level values are on the low / weak side as well. And the OFDM channel is indeed borked ! We've seen this here before, where Comcast places an OFDM channel too high in the frequency range near the end of the plant's bandwidth capability. Some of their cable plants and equipment still only extend out to 850 or 1000 MHz operation. At 957 MHz, it may be too close to the roll-off point of the plant's bandwidth capability, which explains the weak / out of spec power and SNR level.
You should get the techs involved again to investigate, but this may need to be escalated to their engineering department for correction. Good luck with it !
(edited)
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EG
Expert
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120.4K Messages
2 hours ago
@user_y5pfod @XfinityCliff
Please circle back here and post any possible solutions for the issue here in these open public forums so that all readers here may benefit from the exchange / info. This is in keeping with the spirit for which these public help forums were originally intended. Thank you.
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