What is the NovaStar RC4?
If you run a JT-series traffic sign and want its power switched from the control system rather than by hand, the NovaStar RC4 is the small relay card that does it. A control signal arrives, the relays close, and whatever you wired through them comes on.
Release the signal and the relays open again, which is how the same card switches things off. That is the whole job: a control instruction in one end, a circuit made or broken at the other.
It is not a player, a controller or a receiving card, and it does nothing to your picture. It is the part that lets the sign you already own turn its own power on and off.
An RS485 cable comes in the box with it.
What the RC4 works with
Confirm you have a JT-series product before you order, because that is the only family NovaStar builds the RC4 for. The JT50 and JT100 are the models it names, and the connection diagram in the specification uses a JT50.
Those are NovaStar’s multimedia player cards for transport signage: highway message boards, lane and traffic guidance signs, parking guidance displays. If that is the kind of screen you are maintaining, this card is the matching accessory.
If your screen runs on a sending card and receiving cards instead, this is not the part you want. Relay switching on that kind of system comes from a multifunction card, which does the same job with eight channels and a schedule.
How much can the RC4 switch?
3 A per relay, across four relays, and NovaStar draws a firm line about how you switch mains with them. The contacts are rated 30 V at 3 A on direct current and 250 V at 3 A on alternating current.
On AC, NovaStar states that driving the load straight off the relay is not the recommended connection, and its specification draws the method it does want. The RC4 contacts switch a solid-state relay, that relay carries your load, and the relay takes its own DC supply. Neither part comes in the box, so budget for both.
Wire it the other way and the failure is the quiet kind. Relay contacts weld shut after enough hard switching, so your control system reports the circuit open while the sign stays lit. On a roadside installation nobody notices until someone drives past at night.
Size that solid-state relay to your sign, not to the card.
NovaStar RC4 specifications
The two rows that matter before you order are the relay ratings, which decide whether you also need a solid-state relay between the card and the load, and the board size, which decides whether it fits the space you have.
| Host products | JT series, including the JT50 and JT100 |
|---|---|
| Relay rating, DC | 30 V maximum, 3 A maximum |
| Relay rating, AC | 250 V maximum, 3 A maximum — not recommended as a direct connection |
| Supply voltage | DC 4.5 V to 5.5 V |
| Power draw | 1.5 W maximum |
| Operating environment | −20 °C to +60 °C, 0% RH to 80% RH non-condensing |
| Storage environment | −40 °C to +80 °C |
| Board size | 91.5 mm × 45.0 mm, 16.1 mm tall |
| Weight | 44.7 g |
| Supplied with | One RS485 cable |
Figures come from NovaStar’s RC4 Relay Expansion Card Specifications V1.1.0. The storage range runs colder and hotter than the operating range, so a spare kept in an unheated store is fine as long as it warms up before use.
RC4 datasheet and keeping a spare
Nothing is configured on the card itself, so a replacement is a swap rather than a rebuild. There are no files to save first and nothing to restore afterwards.
That is what makes a spare worth keeping at this price. Transport signs are usually the furthest thing from your workshop, and a second visit to a gantry or a roadside cabinet costs far more than the card. Order the spare with the first one and the trip only happens once.
NovaStar RC4 FAQ
Which NovaStar products does the RC4 work with?
The JT series, and NovaStar names the JT50 and JT100 specifically. It is not an accessory for sending-card and receiving-card systems.
Can it switch mains power directly?
Not as a recommended design. The contacts are rated 250 V at 3 A on AC, but NovaStar states that controlling alternating current straight off the relay is not the recommended connection, and draws the method it wants instead: the RC4 contacts switch a solid-state relay, and that relay carries the load.
What is in the box?
The RC4 card and one RS485 cable. If your load is AC, the solid-state relay and the DC supply that feeds it are separate parts.
Does it need its own power supply?
It runs on DC 4.5 V to 5.5 V and draws at most 1.5 W, taken from the connection to the JT-series product rather than from a separate adapter.
Is there anything to configure on the card?
No. The relays follow the control signal they are given, so a replacement card is a straight swap with no settings to restore.
Can I use it outdoors in a roadside cabinet?
Inside a sealed cabinet, yes. It has no IP rating of its own and its humidity limit is 80% non-condensing, so it depends on the enclosure around it rather than on the card.
I need relay control but do not have a JT product. What should I order?
An MFN300 multifunction card, or the MFN300-B box version. Both give a sending-card system eight relay channels plus a schedule, which is the equivalent function on that kind of screen.
What warranty covers an RC4?
Three years of serial-tracked manufacturer coverage, because these cards come through our authorized US NovaStar channel.
Can I get volume pricing or Net 30 terms?
Yes. Send the quantity for volume pricing, which is worth doing on a sign network where every cabinet takes one. Purchase orders and Net 30 terms may be available for approved schools, government buyers, venues and established integrators.
How do I order an RC4?
Pricing here is per card, and at this price a spare is usually worth adding. Orders placed before 3 PM ET on in-stock items ship the same business day from Florida. Contact us to confirm current availability.
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