Black Box SW590A-R2 Configuring Ports for DTE or DCE, Master Slave Leads passed, Signal direction

CODE OPERATED SWITCH II

To	Set SWB 8
Pass breaks	ON
Ignore breaks	OFF

Lead Pass-Through

This function allows the COS II either to pass hardware-handshake leads to connected devices, or to block them. If they are blocked, the leads will still be used to regulate the 8K internal buffer of the Switch. The following table shows the behavior of the COS II for different combinations of devices.

Master	Slave	Leads passed
DTE	DTE	Master CTS to slave DTR
		Slave CTS to master DTR
DTE	DCE	Master CTS to slave CTS
		Slave DTR to master DTR
DCE	DTE	Master DTR to slave DTR
		Slave CTS to master CTS
DCE	DCE	Master DTR to slave CTS
		Slave DTR to master CTS

To pass or block leads, use SWC 8.

To	Set SWC 8
Pass leads	ON
To block leads	OFF

Text or Graphics Mode

SWD 8 and SWE 8 determine whether the COS II is in Graphics Mode or Text Mode. These same switches also govern the device that will signal the pause when the Switch is in Graphics Mode. (For more information on Text and Graphics Modes, see Sections 4.4 and 4.5).

When set for graphics, the COS II can register (1) only pauses in data coming from the master port,

(2)only pauses in data coming from a slave port,

(3)or pauses in data from all ports, either master or slave. Use ththis chart to configure the switch properly:

	Set	Set
For	SWD 8	SWE 8
Text Mode	OFF	OFF
Graphics Mode,
pause from master	ON	ON
Graphics Mode,
pause from slave	OFF	ON
Graphics Mode,
pause from either	ON	OFF

3.8. Configuring Ports for DTE or DCE

A pair of DIP shunts lies behind each DB25 connector on both the main board and the Expansion Unit. The pair eliminates the need for crossover cable to connect devices to the Switch. You can use standard straight-through cable may be used instead, with the DIP shunts acting as crossovers.

A shunt jumper lies in each shunt marked DCE. To change the port configuration to DTE, just pry the jumper gently from its current shunt, and insert it in the DTE DIP shunt.

The chart below provides the signal direction for the main RS-232 lines.

Configured as	Signal direction	Configured as
DTE Port		DCE Port
TXD (2)	Output from unit	RXD(3)
RXD (3)	Input to unit	TXD (2)
RTS (4)	Output from unit	DCD (8)
CTS (5)	Input to unit	DTR (20)
N/A	Output from unit	DSR (6)
DCD (8)	Input to unit	RTS (4)
DTR (20)	Output from unit	CTS (5)
RI (22)	Input to unit	N/A

16