Emerson ROC827 instruction manual EIA-232 RS-232 Serial Communications, BASE-T Crossover Cable

ROC827 Instruction Manual

greater than 400°C (752°F), use plenum rated cables to ensure that cable attenuation remains within specification.

When connecting two twisted-pair Medium Attachment Units (MAUs) or repeaters together over a segment, wire the transmit data pins of one eight- pin connector to the receive data pins of the other connector, and vice versa. There are two methods for accomplishing 10BASE-T crossover wiring:

ƒUsing special cable.

ƒWiring the 10BASE-T crossover inside the hub.

For a single segment connecting only two devices, provide the signal crossover by building a special crossover cable, wire the transmit data pins of one eight-pin connector to the receive data pins of the other connector, and vice versa. Refer to Figure 5-4.

Signal

Pin 1 TD+

Pin 2 TD–

Pin 3 RD+

Pin 6 RD–

Signal

Pin 1 TD+

Pin 2 TD–

Pin 3 RD+

Pin 6 RD–

Figure 5-4. 10BASE-T Crossover Cable

5.7EIA-232 (RS-232) Serial Communications

The built-in EIA-232 (RS-232), the LOI, and the communication modules meet all EIA-232 (RS-232) specifications for single-ended, asynchronous data transmission over distances of up to 15 meters (50 feet). EIA-232 (RS-232) communication provides transmit, receive, and modem control signals. The LOI port also meets EIA-232D (RS-232D) specifications.

The EIA-232 (RS-232) communications have the following communication port designations in ROCLINK 800.

ƒLOI – Local Port EIA-232 (RS-232D). Refer to Section 5.5, “Local Operator Interface.”.

ƒBuilt-in– Comm2 EIA-232 (RS-232C).

ƒModule – Comm3 to Comm5 EIA-232 (RS-232C).

EIA-232 (RS-232) uses point-to-point asynchronous serial communications and is commonly used to provide the physical interface for connecting serial devices, such as gas chromatographs and radios to the ROC800-Series. The EIA-232 (RS-232) communication provides essential hand-shaking lines required for radio communications, such as DTR and RTS.

Issued Mar-06 Communications 5-9