CH1794 Cermetek Microelectronics, CH1794 Datasheet - Page 7

• Manufacturer Part Number: CH1794
• Manufacturer: Cermetek Microelectronics

Specifications of CH1794

• Lead Free Status / RoHS Status: Supplier Unconfirmed

Cermetek Microelectronics, Inc.
code 0) or the command is valid or accepted, or with
an ERROR (result code 4) if the command is not
recognized. The detail contained in the error result
codes signaled to the DTE depends on the level of
message suppression employed by the user. As can
be seen from Tables 5A, 5B and 5C, specifying X4
allows the HS Modem to utilize the entire range of
non-extended messages, whereas X0 suppresses all
but the very basic result codes. Most of the result
codes allowed under X1, X2 and X3 are considered
call progress status codes and, in practice, are
suppressed except for the case of debugging
activities. It is recommended that the non-extended
result codes be used in all cases.
It should be noted that the default connect result codes
9-20 indicate DTE connection speed, not Carrier Line
DCE speed.
maximum speed of 19.2kbps (result code 16). The
CH1799 will connect at a maximum DTE speed of
38.4kbps (result code of 17) and the CH2056 will
connect at a maximum speed of 57.6kbps (result code
18) unless the DTE is forced to a higher speed by
selection of data compression.
maximum DTE to modem speed is 230.4kbps (result
code20).
Extensions to the basic result code set may be
specified by Register S95, which allows for the use of
result codes 40-64, 165-194.
LEASED LINE OPTION
The CH1799LL is a leased line version of the CH1799.
Whereas the CH1799 requires an active voltage
bearing or wet PSTN line for normal operations
(typically, 48VDC on-hook line voltage), the CH1799LL
is designed to operate over a non-voltage bearing or
dry line.
The CH1799LL will only operate properly on a dry line.
Damage will occur if used on a wet line.
CH1799LL does not support ring detect but does
support
Application Note # 116 for examples and instructions
to establish a connection over a leased dry line wire
pair. Note that the length of the leased line is limited
to 20,000 feet.
recommended in Figure 6B and in Cermetek
2004 Cermetek Microelectronics, Inc.
Result codes 53-64 are supported by the CH1799
and CH2056.
supported by the CH2056. To obtain a detailed
status report for a given modem communication
configuration, use the AT\V1 command. Executing
this command at setup will cause the modem to
connect and return a message on line consisting of
<DTE speed> <modulation> <error protocol> <line
speed of connection>.
off-hook
Hence, a CH1794 will connect at a
IMPORTANT NOTE
Result codes 165-194 are only
control.
Use PSTN line protection as
Refer
In this case, the
to
Cermetek
The
Page 7
Application Note # 126.
requirements for FCC Part 68 compliance. The User
is responsible to ensure that FCC Part 68 compliance
is maintained.
As an alternative, the CH1799 will operate on a leased
line if the line is made wet by application of a DC
voltage. Refer to Cermetek Application Note # 114
Table 4.
Modem Family.
NOTES:
1. * Indicates a difference between the CH1786 and
2. NC signifies ‘No Connect.’
Operation of the CH1799LL on a standard PSTN
line will damage the CH1799LL and void its
warranty. Further, operation of the CH1799LL on a
dry line without using proper current limiting circuitry
as outlined in Cermetek Application Note # 126 may
cause damage to the CH1799LL and will also void
its warranty.
PIN
10
11
12
13
14
15
16
17
18
19
20
21
22
1
2
3
4
5
6
7
8
9
the HS Modem. The HS Modem may be directly
substituted for the CH1786 except in applications
where pins 3, 4, 8, 12, or 18 are used.
CTS (FX only)
Pin Comparison of CH1786 and HS
CH1786
SLEEP
RING
GND
RXD
DSR
DCD
RXA
SPK
TXD
DTR
RST
TXA
V/D
V
TIP
NC
NC
NC
HS
NC
RI
Document No. 607-0003 Revision K6 (08/04)
CC
WARNING
High Speed Modem and FAX Family
Follow all applicable
HS Modem Family
OPEN*
OPEN*
RING
GND
RXD
DTR
DSR
DCD
SPK
TXD
CTS
RST
RTS
NC*
V
TIP
NC
NC
NC
NC
T1
RI
CC
.