HEIDENHAIN TNC 335 Technical Manual - Manual (Page 531)

8-24
TNC 360 2 TNC data interfaces 8/95
DTR: Polled by peripheral; it is logic "1" if TNC is ready for service.
DSR: Polled by TNC.
LOW level => ext. data input/output not ready.
HIGH level => ext. data input/output ready.
Software handshaking
Bit 3 determines whether the TNC stops transfer from an external device with control character
. Transfer is resumed with character .
If transfer is stopped with character , up to 12 characters can still be stored. The remaining
incoming characters are lost. Software handshake is normally recommended when interfaces are
connected to an external device.
The following pin layout is possible for the external device:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
• •
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
ge
gn
rs
gr
br
rt
bl
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
• •
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
•
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WH/BN
GND Chassis
RXD
TXD
CTS
RTS
DTR
GND Signal ground
DSR
GND
TXD
RXD
RTS
CTS
DSR
GND
DTR
V.24-Adapter-Block
RS-232-C Adapter block
• •
•
• •
• •
Peripheriegerät
Peripheral unit LE
ws/br
WH/BN
GN
Yl
GY
PK
BL
RD
BN
A HEIDENHAIN standard cable, ref. 242 869, is recommended.
If the TNC is transmitting data, it reacts both to hardware and software handshakes, regardless of
the setting in the MP5020.
If the TNC is receiving data, and no transmission stop is set in the MP5020, the TNC stops the
peripheral unit with the software handshake.
If transmission stop by both RTS and by DC3 is active, the TNC stops transfer with the hardware
handshake.
Character parity
Bits 4 and 5 determine the type of parity check (see Section "Checking data").
Stop bits
Bits 6 and 7 determine the number of stop bits sent at the end of a character.