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CHAPTER 3: Installation

3.1.4 CTS D

ELAY

(W9 J

UMPER

)

When the transmitter of a device is first turned on, an unstable carrier signal is

transmitted for several milliseconds. If data was sent during this period, it would be

received as distorted information. Setting a CTS delay on the RS-232↔485/422

Converter allows the communications link to settle down before data can be sent.

RS-232↔485/422 Converter as DCE (XW1A 8-Position Shunt)

When the RS-232↔485/422 Converter is configured as a DCE device (DIP shunt

in position XW1A), jumper W9 controls the amount of delay from the time RTS

(jumper W5 in the A-B position) is received true until CTS is asserted true. If W5 is

in the B-C position, CTS will be inhibited if an RS-485 carrier is present when RTS

is raised. To select a CTS delay period, set jumper W9 to the 0-, 10-, or 30-msec

position. Regardless of the delay setting selected, when RTS goes false, CTS will

immediately go false. If jumper W9 is in the “ON” position, CTS will follow RTS.

RS-232↔485/422 Converter as DTE (XW1B 8-Position Shunt)

When the RS-232↔485/422 Converter is configured as a DTE device (DIP shunt in

position XW1B), CTS is not supported.

3.1.5 RS-485 D

RIVER

NABLE

(W15)

The RS-232↔485/422 Converter’s RS-485 driver can be set to be enabled one of

three ways: by RS-232 control signals, by data, or constantly on via W9 set in the

ON position).

Driver Enabled by RS-232 Control Leads

If your equipment raises CD or RTS when it is ready to send data, you can set the

RS-485 driver to be enabled by one of these leads. If your equipment does not have

the capability to raise CD or RTS, you will need to set the RS-485 driver to be

enabled by data or constantly enabled.

In order for an RS-232 control lead to enable the RS-485 driver, W15 must be in

position A-B and W9 must be set for 0, 10, or 30 ms.

• When the RS-232 port is selected as DTE (DIP shunt in the XW1B position),

the RS-485 driver will be enabled when CD (pin 8 of the RS-232 connector)

goes true.

• When the RS-232 port is selected as DCE (DIP shunt in the XW1A position),

RTS enables the driver.

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