CH1787(1998) View Datasheet(PDF) - Cermetek Microelectronics
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CH1787 Datasheet PDF : 13 Pages
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Table 4. CH1787 System Data Mode Compatibility Specifications
Parameter
Specification
Parameter
Specification
Asynchronous
Asynchronous
Speed Range
2400, 1200, 600 bps character
asynchronous. 0-300 bps asynchronous
TxD may differ +1%, -25% from modem
output. Offsets will be corrected by
adding/deleting stop bits.
Receive Carrier Frequencies Originate +7Hz 2400Hz +7Hz
V.22 bis, V.22, 212A
Answer
1200Hz +7Hz
Bell 103
Answer 'space'
Answer 'mark'
Original 'space'
Original 'mark'
2025Hz +7Hz
2225Hz +7Hz
1070Hz +7Hz
1370Hz +7Hz
Asynchronous
Format
8, 9, 10 bits, including start, stop, parity
Receiver
Sensitivity
OFF to ON threshold-43 dam
ON to OFF threshold-48 dam
Telephone Line
Interface
Two-wire full duplex over public switched
network. On-chip hybrid and billing delay
timers.
Modulation
V.22 bis, 16 point QAM at 600 baud. V.22
and 2212A, 4 point, DPSK at 600 baud. Hysteresis
103 binary phase coherent FSK.
Self Test
Pattern Generator
Alternate 'ones' and 'zeros' and error
detector, to be used along with most
loopbacks. A number indicating the bit
errors detected is sent to DTE.
Line Equalization
Transmit Carrier
Frequencies
V.22 bis V.22,
212A
Originate 1200Hz+.01%
Answer 2400Hz+.01%
Diagonostics
Available
Bell 103 mode
Originate 'space'
Originate 'mark'
Answer 'space'
Answer 'mark'
1070Hz+.01%
1270Hz+.01%
2025Hz+.01%
2225Hz+.01%
Call Progress
Tones Detected
Computer Interface
2 dB minimum
Fixed compromise equalization,
transmit.
Adaptive equalizer for PSK/QAM,
receive.
Local analog loopback.
Local digital loopback.
Remote digital loopback.
Request remote digital loopback.
Local interface loopback modem with
self test.
With speaker or quiet screen
messages
(no dial tone, busy, ring-back, modem
answer tone and voice).
IBM PC/XT/AT bus compatible with an
8250/16450/16550A UART as a serial
controller.
Cermetek Microelectronics, Inc.
Document No. 603-0182 Rev. D (11/98) 10
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