RS-232C interface (continued)

Software specifications (protocol)

1.Communication parameters

Communicati

Asynchronous, full duplex

on system

 

Transfer rate

300, 600, 1200, 2400, 4800 or 9600 bps

 

 

Bit length

7 bits or 8 bits

Stop bit

1 bit or 2 bits

 

 

Parity bit

None, odd or even

 

 

ACK code

Returned or not returned

 

<Note>

 

ACK is the code which is returned from the VTR

 

to the controller when data has been successfully

 

sent from the controller.

 

 

The underlining (__) denotes the factory setting mode.

The settings can be changed in the following Setup Menu.

Communicati

Setup menu item

on parameter

Transfer rate No.205 BAUD RATE

Bit length No.206 DATA LENGTH

Stop bit No.207 STOP BIT

Parity bit No.208 PARITY

ACK code No.209 RETURN ACK

2.Send format [controller (PC) > VTR]

The following responses are for command instructions. Multiple responses may be made if necessary.

_Data format

[STX]

[command]

[:]

[data]

[ETX]

02h

XX XX XX

3Ah

XX.....XX

03h

20H<XX<7FH

(XX=ASCII code: symbols, numbers, upper-case let- ters)

[command]:

This is the command identifier (3 bytes).

A 3-byte identifier (ASCII code: symbols, numbers, upper-case letters) is sent as the command.

[:]:

The colon is the code serving as a delimiter between the command and data.

[data]:

Data (ASCII code: symbols, numbers, upper-case let- ters) can be added in the number of bytes required.

_Outline of procedure for sending data from controller

1The send command starts with STX (start of text =

02h). The command is then identified by COMMAND which follows, and the data is added as required.

The command ends with ETX (end of text = 03h).

2When a different command is to be sent, a response is awaited from the VTR, and then the command is sent. (See page 133.)

3If STX is sent again before ETX is sent, the receive data buffer inside the VTR is cleared. A command error is returned to the controller, and the data is newly processed with STX which was received again at the head.

132