The technology behind remote controls has changed dramatically during my time in this business. When I first started I had a remote control that needed dc continuity between the transmitter site and the studio. That was problematic, to say the least. I also had a system that used a super-audible tone going up to the site on the microwave shot, with metering coming back on an SCA. I had another one with metering coming back on a sub-audible tone on an AM station.

Thankfully those are all long gone.

Remote controls that are around today accomplish the same thing that the older units did, but fortunately the communications links between the two ends are different. Adding POTS accessibility in the mid-1980s was great; but, adding IP accessibility (within the last couple of years) was even better. Typical remote controls can now have HTTP, SMTP, SNMP and NTP functionality, making the life of the typical broadcast engineer a little easier.

Because different manufacturers' products are basically all designed to do the same thing, naturally they have similarities. I'll point out common features, but I also am going to point out the differences that I think may make or break a purchase decision. Some devices have unique features that deserve attention.

Davicom MAC 216

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The first company we'll talk about is Davicom. A more recent player in the field (having started in 1994), the company has an extensive product line. Specifically, I'll look at the MAC 216. The stand-alone unit does not require a CPU at the remote site, although one is needed for local control. It features 16 metering inputs, 32 status inputs, 32 relays available on 50-pin Champ connectors. Inputs and outputs are expandable via Modbus. The metering range is ±2.5V, ±10V, ±20V at 12-bit resolution and 100k ohms loading. The status inputs are optically isolated with a 22k ohms loading. It is accessible via HTTP, NTP, SMTP and SNMP. A POTS connection allows it to calls out with voice messages and respond to DTMF commands.

Programmable actions can be taken on conditions or events, and alarm emails can include HTML or XML file attachments. Up to 128 internal timed events can be programmed. There are no internal moving parts (no HDD or fan). It specifies RF immunity in fields up to 10V/m field intensity. The unit occupies 2RU and is 12" deep.

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