Page 1
A
• Flexible operations in both
Adapters Modems
• Compatibility with a wide range
• Automatic adaptation to
Meets the demands of today’s business environment
for reliable high-throughput telecommunications
IBM 7858 Professional Modem
synchronous and asynchronous
mode
of ITU standards
changes in network environment
• High-throughput telecommunications over switched and
leased lines
• Flexible setup, operation and
management
• Enhanced system security
The IBM 7858 Model 336 is a stand-alone modem with Link Problem Determination
Aid (LPDA) support for those environments requiring centralized management from
a NetView console. It allows your data terminal equipment (DTE) to communicate
with other DTEs using a synchronous or asynchronous protocol. The 7858 operates
in duplex mode at line speeds of up to 33.6 Kbps over switched and 2-wire or 4-wire
leased lines.
52
www.networking.ibm.com
Page 2
Product Overview
Flexible operations in both
synchronous and asynchronous
mode
The 7858 provides flexible operation in
synchronous and asynchronous mode
over switched and 2- or 4-wire leased
telecommunication lines.
Each 7858 modem can be controlled and
configured from the front panel, from a
DTE using AT commands, or NetView
using LPDA commands.
The following command sets are
available:
• Hayes Attention (AT) command set
• ITU V.25bis asynchronous command
set
•ITU V.25bis synchronous command set
• IBM's LPDA commands.
The modem can be configured to
operate in asynchronous or synchronous mode:
• Asynchronous mode:
- AT Command mode / Hayes
Autosynch
- Asynchronous V.25bis Command
mode
- Dumb mode (The modem does not
accept any command from the DTE.)
• Synchronous mode:
- Asynchronous Command mode and
Synchronous Data mode
- Synchronous Command mode and
Synchronous Data mode
- Synchronous V.25bis Command mode
- LPDA-2 mode.
Standards compliance
The 7858 modem supports a wide
range of ITU and industry standards:
®
Digital Interface standards:
•ITU V.24
•ITU V.28
Modulation Mode standards:
• ITU V.21
• ITU V.22 alternative A/B with V.25
autoanswer
• ITU V.22bis
• ITU V.23
• ITU V.32
• ITU V.32 bis and V34
Other standards:
• ITU V.14 Async/Sync conversion with
overspeed range selection
• ITU V.42 Asynchronous error checking
compatible with the Microcom Networking Protocol (MNP) class 4 service.
With this error checking, the data
integrity in asynchronous operation is
as good as typical synchronous
protocols.
• ITU V.42bis data compression compatible with MNP class 5 service
• ITU V.54 loop testing capabilities
• ITU AT and ITU V.25bis Automatic
Calling Interfaces
• IBM LPDA-2 command set for network
management
• Fax support Group 3 Class 1 ITU V.29,
V. 2 7 t e r, a n d V.1 7
Automatic adaptation to a
network environment
The 7858 supports functions that
automatically adapt to the changing
network environment. For example, it
supports auto-mode capability to
automatically select the modulation
scheme at connection setup. This
function determines the appropriate
modulation scheme (V.34, V.32bis,or V.32)
based on compatibility with remote
modem capabilities.
The 7858 also has an adaptive line rate
facility that automatically decreases or
increases the transmission speed to
constantly achieve the highest
performance compatible with the line
quality. It adjusts the speed if telecommunication line conditions degrade or
improve and according to the transmission protocol negotiated at connection
setup.
Switched Network Backup (SNBU)
capability establishes a switched
connection when a leased line is down.
A SNBU connection is associated with
a timer selected at modem setup.
With leased line monitoring one of the
following actions can occur after a time
out, depending on the modem configuration:
• The active SNBU line is released and
the modem switches back to a leased
line. If the leased line is still down, a new
SNBU call is set up.
• The modem switches back to the
leased line operation without releasing
the SNBU line. If the leased line
communication is operational for one
minute, then the SNBU line is released;
otherwise the communication is
resumed through the SNBU line.
The 7858 also incorporates asynchronous speed buffering, which allows the
DTE speed to remain constant even
when the modem-to-modem line speed
changes from call to call. For example,
the DTE speed might be 115.2 Kbps
while the line speed is 33.6 Kbps.
High-throughput telecommunications over switched and
leased lines
The 7858 modem operates on switched
and 2- and 4-wire leased lines. The
supported line and DTE speeds are
listed in the Supported Line and DTE
Speeds table.
A
Adapters Modems
www.networking.ibm.com
53
Page 3
A
Supported Line speeds (Kbps)
Modulation Modem Data Rate
V. 3 4 3 3 . 6 – 2 . 4
V.32bis 14.4 – 4.8
V.32Trellis 9.6
V. 3 2 9 .6 , 4. 8
V.22bis 2.4, 1.2
V.23 1200/75
V. 2 2 1. 2
V.2 1 0. 3
Fax Group 3:
ITU V.29 9.6, 7.2
V.27 ter 4.8, 2.4
V.17 14.4 – 7.2
Supported DTE speeds
Adapters Modems
Speed (Kbps) Synchronous DTE Asynchronous DTE
115.2 No No*
57.6 No No*
38.4 No No*
33.6 Yes No
31.2 Ye s N o
28.8 Yes No
26.4 Yes No
24.0 Yes No
21.6 Ye s N o
19.2 Ye s Ye s
16.8 Ye s N o
14.4 Ye s Ye s
12.0 Yes N o
9.6 Ye s Ye s
7. 2 Ye s Ye s
4.8 Ye s Ye s
2.4 Yes Yes
1.2 Ye s Ye s
0.3 N o Ye s
*In Direct Mode (that is, when data Buffering and Error Control with or without modem compression are disabled)
Directory ser vices
With the 7858 modem, you can define
and store up to 20 different telephone
numbers in Hayes AT mode and 12 in
V.25bis mode. You can also associate a
telephone number with a configuration.
When the number is dialed, the
configuration automatically activates.
Several dial numbers can be linked.
When the first dialed number is
detected as busy, the next number is
dialed automatically.
Factory preset and user configurations
Ten different configurations are preset
and available in the modem. You can
select any of these configurations,
modify it and store it as a user configurat ion.
Automatic dialing
Data transmission over the public
switched network is initiated after a
communication path is established.
Automatic calls can be initiated by the
Auto-call on the public switched
network is feasible using one of the
following commands:
•The Hayes Attention (AT) command set
•The ITU V.25bis command set
•The IBM LPDA-2 call-out and disconnect commands.
In call-originate mode, the 7858
modem automatically selects operation to match the remote modem.
DTE with the V.24/V.28 interface.
54
www.networking.ibm.com
Page 4
Operator panel
The operator panel contains four keys,
five green lights and a display for status
monitoring.
The following operations can be
controlled from the operator panel, from
a DTE or from NetView:
•Machine information display
•Manual operations
•Modem configuration
•Line quality indicators.
Enhanced system security
The 7858 can be password-protected
to disable configuration changes. You
can also associate password protection to stored telephone numbers to
reject incoming calls.
The call-back feature enables you to
link a procedure to stored telephone
numbers. With this feature, for example,
a modem receiving a call can disconnect either immediately after the
answer tone is sent, or after password
checking. The modem can then call
back a pre-stored number or one
provided by the calling party.
A
7858 Professional Modem Specifications
Physical specifications Desktop unit with self-contained power supply
Width: 210 mm (8.27 in.)
Depth: 150 mm (5.91 in.)
Height: 44 mm (1.73 in.)
Weight: 1.2 kg (2.65 lb)
Operating environment •Temperature: 0° to 40°C (32° to 104°F)
•Relative humidity: 8 to 80% noncondensing
•Class B EMC compliant
Power requirements Input voltage: 100 to 127 or 200 to 240 volts nominal
Frequency: 50 and 60 Hz. nominal
Phase: single
Input power: 5 W
Customer setup Comes with power cord, telephone line cables and a
Operational firmware can be upgraded by download transfer to Flash Memory.
NetView support Can be managed from a centralized NetView console through LPDA-2 commands.
Diagnostics Power-on self test
ITU V.54 loop tests can be invoked from the modem front panel or an attached DTE.
Loop tests:
•Local analog test loop (ITU loop 3), including self-test facility
•Digital test loop (ITU loop 2)
•Remote controlled digital test loop (ITU loop 2), including self-test facility.
Guide to Operations
.
Adapters Modems
Supplementary Information
Information on the IBM 7858 Professional Modem is available at:
www.networking.ibm.com
www.networking.ibm.com
55
Loading...