UTP / STP Links Using

Optocouplers as Isolators

Transmisii de date pe cabluri

UTP / STP cu separare prin

optocuploare

Exemplu de circuit de separare

Basic Isolation Circuit ( switch-mode)

Optocoupler Interface provides dual Light-Barrier to protect the transmitter

BALUN :

BALUN = Balanced – Unbalanced Mode

Semi-duplex Link Uses Optocouplers to Isolate Both Directions

Serial Interface Takes 4-Optocouplers to Achieve Bi-directional Communication

Typically distorted rectangular wave shows reflections

Current Loop

Variations in line-impedance are rejected

Signal Formats

Simple : Unbalanced termination of an UTP link

uses a voltage signal for transmission, and an

optocoupler to isolate the receiver from

the line

Overvoltage protection clamp

does not alter isolation and preserves tramsmission speed

Stronger Clamprecommended for higher current UTP links

Differential UTP communication also allows

mutual protection of transmitting LEDs

Differential UTP-transmission also providing bi-polar clamp

For most reliable transmission Current-loop is recommended

Current-mode link termination can be easily made bi-polar by using a Graetz-bridge