What the maker puts in writing
- “The digital TV converter box, converts digital air channels to your analog TVs”
- “[ATSC BOX] The tuner box is programmed to receive local over-the-air (OTA) channels through ATSC signals”
- “[CLEARQAM COMPATIBLE] This converter box supports ClearQAM and can be used with a cable provider to watch unscrambled cable channels”
- “[TV RECORDING] iView-3500STBIII digital converter box with clock function supports TV recording function”
- “[UNIVERSAL MEDIA PLAYER]… Supports up to 4TB portable hard drive”
- Title: “Channel 3/4, HDMI, A/V, USB, Learning Remote”
The learning remote is the feature nobody else has
A converter box adds a second remote to the room, and you need both: the television’s to set volume and input, the box’s to change channel.
A learning remote copies the other one. You hold your television’s remote facing the box’s, press the button you want to teach, and the handset records the infrared pattern. Teach it the TV’s power and volume, and you are back to one remote.
No other product on this shelf offers it — not iView’s own 3300STB at $28.95, not the $159.99 ADTH, nothing.
Mediasonic’s answer to the same problem is different and also useful: a “LARGE Remote Control”, which is the other thing people actually want from a box like this.
Three outputs, and the third one is the point
HDMI for a modern television. A/V (composite) for one with yellow, red and white sockets. And Channel 3/4 for one with nothing but an antenna input.
That last is an RF modulator: the box generates an analog television signal on VHF channel 3 or 4, you connect it to the antenna input with coaxial cable, and tune the set to that channel. It is the only way to use a very old television, a portable set, or many RV and marine sets.
Mediasonic describes its version more precisely — “Channel 3 / 4 hard switch for old TV” — and the word hard matters: a physical switch rather than a menu option, because you cannot read an on-screen menu until the television is already on the right channel. This listing does not say which kind it has.
The fullest output set on this shelf belongs to allaboutadapters: “simultaneous HD out, component YPbPr out, composite RCA and RF A/V output”, plus S/PDIF digital audio.
But the ATSC version is unaddressed
The bullets say “ATSC” without a number, which means ATSC 1.0 — the United States digital broadcast standard since 1998.
ATSC 3.0 (“NextGen TV”) is its successor, carrying 4K and HDR with better reception, and broadcasters are transitioning station by station. As a channel moves to 3.0, a 1.0-only box stops receiving it.
Only the ADTH at $159.99 handles both. Only the Mediasonic at $39.99 warns that it does not: “This Box does NOT support ATSC 3.0.”
Eight listings here, this included, do not raise it.
And its near-twin costs a dollar more for a title
3500STB III — $32.96 — bullets on the converter function, ATSC, ClearQAM, recording, media player
3500STBA III — $33.97 — the same five bullets, word for word
Both even call themselves “iView-3500STBIII” in the recording bullet.
The published differences: the letter A and the words “(New Firmware)” in the dearer title; a weight (567 g (20 oz)) on the dearer one and none here; and dimensions that contradict each other — 8.66 × 5.79 × 1.57 in (220 × 147 × 40 mm) here against 8.66 × 1.77 × 7.95 in (220 × 45 × 202 mm) there, which cannot both be the same cabinet reordered.
Four terabytes, and the limits the other listings reveal
This publishes “up to 4TB portable hard drive” and no filesystem.
The ZJBOX publishes one, and it exposes a constraint the rest leave out: “external hard drives with a FAT32 file system capacity of up to 4TB”. FAT32 cannot hold a file larger than 4 GB, so a high-definition recording beyond roughly two hours either fails or splits. And Windows will not format a 4 TB drive as FAT32 with its standard tools.
Mediasonic adds the other warning: use a hard drive, because “USB flash drive is not recommended” — recording writes continuously, and a flash drive’s sustained write speed and write endurance are both poor for that. Mediasonic also caps its own support at 2 TB, half what these boxes claim.
What is not published
No warranty. ZJBOX alone publishes a term: “1 year Warranty”.
No antenna, which every box on this shelf requires. ZJBOX says it plainly — “requires an external antenna… It does not have signal reception or amplification functions” — and only the Tablo supplies one.
No HDMI cable, where Mediasonic supplies a 5 ft one and ZJBOX supplies HDMI and composite both.
No front display, where Mediasonic shows channel and sub-channel plus a standby clock, and allaboutadapters has a “large LED digit panel”. United States digital channels are numbered 7.1, 7.2, 7.3 — so a display without sub-channels is much less useful, and no display at all means turning the television on to see where you are.
No weight.
Prices quoted in this text were read on October 4, 2026. The live price is at the top of the page.
