Siemens SINAUT ST7 - MID On Character Recognition

Operating Modes and Character Recognition
© Siemens AG 2002 All Rights Reserved 6NH7811-0AA22
MD2 Modem (07/2002)
4-25
4.2.3 "MID on" Character Recognition
The "MID on" character recognition (MID = Message Interval Detection) is
designed to transmit a data steam consisting of characters of any format. This type
of character recognition is especially suited to transmit data streams which are
available from the DTE at only half or a quarter of the baud rate set on the modem.
This means that data can be transmitted at 300 or 600 bps when the modem's
baud rate is set to 1200 bps.
Another characteristic of the "MID on" character recognition is that the idle state of
the data signal on the WAN line can be set to either "0" or "1". The MD2 detects
intervals between two messages by the idle state of the data signal. These
intervals must last at least 12 or 24 bits long.
Fig. 4-23 Example of message interval detection using "MID on (interval ³ 12) idle state 0"
The following table summarizes the various characteristics of "MID on" character
recognition.
Table 4-4 Summary of the characteristics of the "MID on" character recognition
Character recognition Settings on the 10-pin
DIL switch
Length of
message
interval
Idle state of
the data
signal
Possible
baud rates
(in baud)
MID on (interval ³ 12)
idle state 0
0
MID on (interval ³ 12)
idle state 1
³ 12
bits long
1
600, 1200,
2400, 4800,
9600, 19200
MID on (interval ³ 24)
idle state 0
0
MID on (interval ³ 24)
idle state 1
³ 24
bits long
1
300, 600,
1200, 2400,
4800, 9600,
19200
Message interval
detected
min. 12 bits long
Message
1234
OFF
ON
5678910
1234
OFF
ON
5678910
1234
OFF
ON
5678910
1234
OFF
ON
5678910