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參數(shù)資料
| 型號(hào)： | MT884 |
| 廠商： | Mitel Networks Corporation |
| 英文描述： | () |
| 中文描述： | （） |
| 文件頁(yè)數(shù)： | 4/11頁(yè) |
| 文件大?。?/td> | 87K |
| 代理商： | MT884 |
MSAN-144
Application Note
A-232
Data Transmission Methods and
Message Formats
The CNIC can process a FSK modulated signal
carrying information compatible with any of the three
data transmission methods specified by TR-NWT-
000030:
On-hook data transmission associated with
ringing,
On-hook data transmission not associated with
ringing,
Off-hook data transmission.
The SPCS data interface supports single data
message and multiple data message formats. In the
single data message format, information is sent to
the CPE as a series of data words specifying
message type, message length, message data and
error detection information. In the multiple data
message format, information sent to the CPE is
similar to the single message format except the
message data field is replaced by a series of
parameter messages. Each parameter message
consists of data words specifying parameter type,
parameter length and parameter data.
For single and multiple data message formats each
word shall consist of an 8-bit data byte preceded by
a start bit (space) and followed by a stop bit (mark).
The least significant bit of each data byte shall be
transmitted first. The Mark bits (maximum ten bits of
high) may also be inserted between message words
when necessary. Since the FSK modulation is used
in both data message formats, the differences
between the two formats are transparent to the
CNIC.
Briefly, the CND multiple data message format
consists of the following:
Field (1):
The channel seizure signal, used for on-
hook data transmission only, is a block of
300 continuous bits of alternating "0"s
and "1"s. The first bit to be transmitted is
"0" while the last bit is "1".
Field (2):
The Mark signal is composed of 80
±
10
bits of continuous high.
Field (3):
1 byte of Message type word.
Field (4):
The Message length is the 1-byte
information that specifies the total
number of message data words (for
single
data
message
parameter words (multiple data message
format) sent to the CPE, excluding the
final checksum.
format)
or
Field (5):
Parameter messages can consist of N
parameters and each parameter is
further divided into three sub-fields in the
order shown below:
Parameter Type Word (1 byte)
Specifies the interpretation of the
sub-field Parameter Data Words.
Possible message types include:
time, dialable directory number
(DDN), absence of DDN and call
qualifier.
Parameter Length Word (1 byte)
Equals the number of data bytes
contained in the Parameter Data
Words sub-field.
Parameter Data Words
Possible data words include: date,
time, incoming call number and
reason for absence of DDN. Note
all data bytes in this sub-field are
encoded in ASCII format.
Field (6):
1
complement of {field (3) + field (4) +
field (5)} mod 256.
byte
binary
checksum
=
2's
mk:
mark bits (0-10)
Application Circuits Using the MT8841
Five Function Telephone Line Interface
The telephone line interface in Figure 2 performs five
basic functions, mentioned previously. It terminates
the line with 600 ohms, provides high voltage
isolation, provides common mode rejection with a
differential input, detects ringing, and converts the
calling number FSK signal to a serial data format.
During FSK signal reception, the line must be
terminated with 600 ohms AC coupled. A termination
circuit with relay and relay driver is typically used for
channel
seizure
signal
(1)
mark
signal
(2)
message
type
word
(3)
message
length
word
(4)
parameter
messages
(5)
check
sum
word
(6)
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MT8860 | DTMF DECODER |
| MT8860XC | DTMF DECODER |
| MT8860XE | DTMF DECODER |
| MT8865 | DTMF Filter |
| MT8865XC | DTMF Filter |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MT8840 | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:ISO2-CMOS Data Over Voice Modem |
| MT8840-1 | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:ISO2-CMOS Data Over Voice Modem |
| MT8840AE | 制造商:Rochester Electronics LLC 功能描述: 制造商:MITEL / ZARLINK 功能描述: 制造商:Zarlink Semiconductor Inc 功能描述: |
| MT8840AS | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:ISO2-CMOS Data Over Voice Modem |
| MT8841 | 制造商:MITEL 制造商全稱:Mitel Networks Corporation 功能描述:CMOS Calling Number Identification Circuit |
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