Digital Serial Interface

Digital Serial Interface is a protocol for the controlling of lighting in buildings (initially electrical ballasts). It was created in 1991 by Austrian company Tridonic and is based on Manchester-coded 8-bit protocol, data rate of 1200 baud, 1 start bit, 8 data bits (dimming value), 4 stop bits, and is the basis of the more sophisticated protocol Digital Addressable Lighting Interface.

The technology uses a single byte to communicate the lighting level (0-255 or 0x00-0xFF). Digital Serial Interface was the first use of digital communication in lighting control, and was the precursor to DALI.

Advantages

• Its simple nature makes it straightforward to understand, implement, and diagnose, while its low voltage means it typically runs along relatively thin cables.

• Because each device has its own wire to the controller (rather than being part of a network) it has no need of an address to be set, so can be replaced simply by unplugging the faulty one and plugging in the new.

• It dims to off, so does not require mains switching equipment to turn them off.

Disadvantages

• It requires one wire per control channel so a sophisticated system could have hundreds of wires, thereby making diagnoses of problems difficult.

• It is a proprietary standard initially exclusive to Tridonic and mainly brands of Tridonic's parent company Zumtobel.

Rival protocols

• Digital Addressable Lighting Interface
• 1-10v analog

Digital Addressable Lighting Interface

Main article: Digital Addressable Lighting Interface

Digital Addressable Lighting Interface is an open standard for digital control of lighting. Several companies have adopted the Digital Addressable Lighting Interface protocol in their product offerings. Even though Digital Addressable Lighting Interface is an open standard, there are already versions of its implementation emerging in different lighting manufacturers products as they strive to provide a point of difference. Digital Serial Interface is essentially the same technology as Digital Addressable Lighting Interface in terms of messaging, however, Digital Serial Interface eliminates the individual addressing aspect of each light fitting found in Digital Addressable Lighting Interface.