Black Box PCW22A-R3, PCW22A-R4 manual 2 SW2

PROTOCOL CONVERTER A/S-2G

Block size for the 2770/2780 is normally limited to 160, but block size is 400 if the 2770/2780 has the Multiple Record Transmission. Block size for the 3780 is 512.

Switch #4	ON	=	sends CR LF (Carriage Return, Line Feed) to asynchronous device immediately after
			each logical end of block character (ETB, or ETX) is received from the synchronous
			side.
	OFF	=	Normal operation
Switch #5	ON	=	Variable-length blocks. This switch causes the records sent by the asynchronous
			device to be blocked and treated as variable length, i.e. no spaces are used to pad
			out the block.
	OFF	=	All blocks are treated as fixed length, which would require blank spaces, if necessary,
			to complete the block size. (In 2780 multi-record blocks, an IUS character is
			inserted after each 80 characters counted. The final record is the only one that may
			be less than the block size specified).

NOTE

It is possible that a block will have only one record if you enter a CR after each record (2780 mode).

Switch #6 ON = 3780 MODE

OFF = 2770/2780/3741 MODE

Switch #7 ON = When RAM reaches a nearly-full state, DTR (Pin 20) will be lowered. When RAM space is available, DTR will be raised to permit transmission to resume. Port A must be configured as DTE (see Section 3.2.5). When CTS from the external asynchronous device is ON, the A/S-2G can send data. When the external device lowers CTS, the A/S-2G will not send data.

OFF = When RAM reaches a nearly-full state, an X-OFF (ASCII DC3, 13 Hex) will be issued to the asynchronous device to prevent buffer overrun. When RAM space is available, X-ON (ASCII DCl, 11 Hex) will be sent to resume transmission. Put the CTS A jumper to the on position (see Section 3.2.3).

Switch #8 ON = 2 Stop Bits (asynchronous side only).

OFF = 1 Stop Bit (asynchronous side only).

3.2.2 SW2

Locate the switch labeled SW2 on the printed circuit board. (See Figure 5-2 on page 28.)

Switch #1	ON	=	Space compression on transmit (3780 Mode only).
	OFF =		Normal operation.
Switch #2	ON	=	Pass escape sequences through.
	OFF	=	Convert escape sequences to CR LF or FF per Section 4.2.3 on page 20.
Switch #3	ON	=	No Asynchronous RTS except during bisynchronous receive (half-duplex on
			asynchronous side).
	OFF	=	Normal Operation (full-duplex).

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