Gossen IPP 144 - 40 GE User Manual download pdf (Page 34)

Improved handshaking for pre-stored texts

After receiving the control command <CR> the printer now

sets RTS at „BUSY“ or the signal XOFF is transmitted.

When the printing of pre-stored text is complete, RTS is

reset or the signal XON is transmitted.

This handshake can be used to control the data

transmission and prevent rapid text calls being lost or

overwritten.

Note:

Without Handshake the following can occur, if the text

calls are sent in too quickly:

Data input:

Actual Print-out:

Machine No. 3 pre-stored Text No. 1

2 just „2“ printed, Text No. 2 missing

3 just „3“ printed, Text No. 3 missing

XON / XOFF

The report functions „Printer read/not ready“ are handled

by this protocol if no handshake lines are connected

(RS 232 C, RS 422 or RS 485).

This function only applies to the E version, interface II.

XON is transmitted if the IPP 144-40 GE is ready to

receive.

XOFF is transmitted if the IPP 144-40 GE is not ready

to receive (see above).

Note:

If the IPP 144-40 GE is not ready to receive, it transmits

this character just once, not continuously.

No adjustments have to be made, this protocol always

runs parallel to the hardware handshake.

During the preset wait delay the interface is not ready to

receive. After expiry of the wait delay the RTS signal

(or XON) becomes active again and requests the subse-

quent transmission.

The next interval begins upon receiving of <CR> or

<CR + LF>. <LF> on its own is not accepted.

interval

(serial)

1 2 ... 29 30 31 32 33 34 35 36 37 38 39 ... 63 64

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Gossen IPP 144 - 40 GE User Manual Page 34