Black Box SME-4M 用户手册

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页码 3
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FEATURES
• Replaces two modems in point-to-point
applications.
• Speeds up to 38.4 kbps.
• Small and lightweight. Easy to install
or replace in the field.
• LEDs show DSR, CTS, and TXD for
both ports.
• Front-panel switches set signals and
select test mode.
• Operates transparently, sync or async.
IBM compatibility at two different speeds. Runs sync or async, too!
OVERVIEW
The Synchronous Modem Eliminator (SME-4M) enables
a mainframe or minicomputer to communicate locally with
another mainframe, minicomputer, or remote controller. 
And best of all, it saves you money because the SME-4M
replaces the two modems or line drivers normally needed 
for such communication.
Just one versatile SME-4M enables asynchronous, 
synchronous, or bisynchronous communications between 
two DTEs over RS-232C cable.
In synchronous mode, the unit operates at data rates that
top out at 38.4 kbps. Plus the SME-4M operates transparently
in either synchronous or asynchronous mode. You can also
configure the SME-4M to operate at some nonstandard data
transmission speeds. To set the SME-4M for one of these
speeds, configure the unit according to the chart on the right.
The SME-4M is small and lightweight, so it’s easy to handle.
And because no special tools are needed, installation is simple.
The modem eliminator’s front panel has six LEDs and
three switches. The six LEDs indicate Clear To Send (CTS),
Transmitted Data (TXD), and Data Set Ready (DSR) for each
port. The three switches include Ring Indicator (RI) and
Control Data Set Ready (CON) signals, and (LB) selects the
Digital Loopback Test Mode.
Use the SME-4M’s diagnostic loopback capability to test
asynchronous applications. Simply press the switch and enter
data at the host terminal or computer. That data should
return to you exactly as you sent it.
The unit fits neatly on a desktop. Each SME-4M is shipped
with a 115-VAC power transformer and a user’s manual.
SME-4M
(ME251A-R3)
IBM
®
mainframe
RS-232 Cable 
(ECM25C)
RS-232 Cable 
(ECM25C)
S/3X or 
AS/400
®
host
2/22/2007
#10205
724-746-5500
   blackbox.com
Strap Position
Transmission Rate (bps)
a
76,800
b
153,600
38,400
38,400
19,200
19,200
9600
9600
4800
4800
2400
2400
1200
1200
Crystal Frequency
2.4576 MHz
Buyer’s Guide
Transmission Speeds