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Products   >   I/O Expansion Modules   >   Communications Modules   >   Emerald-MM-4M 4-Port Serial Module

Emerald-MM-4M 4-Port Serial Module

4-Port RS-232/422/485 PC/104 Module

Emerald-MM-4M 4-Port Serial Module: I/O Expansion Modules, Rugged, wide-temperature PC/104, PC/104-<i>Plus</i>, PCIe/104 / OneBank, PCIe Minicard, and FeaturePak modules featuring standard and optoisolated RS-232/422/485 serial interfaces, Ethernet, CAN bus, and digital I/O functions., PC/104
Configuration Options
I/O Headers
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Our Emerald-MM PC/104 module gives you 4 serial ports operating at speeds up to 115kbps.

In RS-232 mode, the full complement of standard PC serial port signals (8 signals + ground) are provided for each port and are grouped onto two 20-pin headers (2 ports per header). In RS-422 mode, Signals RX+, RX-, TX+, and TX- are provided, along with ground. In RS-485 mode, signals TX+/RX+ and TX-/RX- are provided, along with ground.

A 16C554 quad serial port IC is used for the serial ports. This chip supports data transfer rates up to 115kbps and contains a 16-byte programmable FIFO buffer for each port to minimize processor overhead.

Flexible Configuration

Emerald-MM offers more interrupt level and I/O address options than other quad serial port modules. Therefore, integrating the board into your computer system is a simpler task. Eight different I/O address combinations and 10 different interrupt levels are available.

Full Interrupt Sharing

Any number of ports can share the same interrupt level. And if you have two boards in one system, both boards can share the same interrupt level as well. An interrupt status register is provided to indicate the status of each serial port's interrupt request signal. This register is especially useful in Windows NT.

Designed for the Embedded World

Another distinguishing feature of Emerald-MM is its low-power +5V only operation. This board needs absolutely no +12V or -12V to operate. Extended temperature operation of -40°C to +85°C is also standard.

Configuration Options

I/O Address Selection (Hex)

Selection Port 1 Port 2 Port 3 Port 4 Status Register
0 3F8 2F8 3E8 2E8 220
1 3E8 2E8 3A8 2A8 220
2 380 388 288 230 224
3 240 248 260 268 224
4 100 108 110 118 240
5 120 128 130 138 244
6 140 148 150 158 248
7 160 168 170 178 24C

Interrupt Levels

Interrupt levels are individually selectable for each port. The available interrupt levels are 2, 3, 4, 5, 6, 7, 10, 11, 12, and 15. In addition, a 1K Ohm pulldown resistor is provided for each port.

A single interrupt level can be shared by 2, 3, or 4 ports on one board and can even be shared by more than one board in the system. To enable interrupt sharing, set two or more interrupt level jumpers to the same level and pull out all but one pulldown resistor jumper.

I/O Headers

Emerald-MM has two 20-pin I/O headers with two serial ports on each header. These headers mate with standard ribbon cable connectors. Our cable no. C-DB9M-18 provides a 20-pin IDC connector at one end to mate with the pin headers on the board, and it has two DB-9 male connectors at the other end with the standard PC serial port pinout. Each cable handles two ports; two cables provide access to all four ports on the board.

DCD 1 1 2 DSR 1
RXD 1 3 4 RTS 1
TXD 1 5 6 CTS 1
DTR 1 7 8 RI 1
GND 9 10 N/C
DCD 2 11 12 DSR 2
RXD 2 13 14 RTS 2
TXD 2 15 16 CTS 2
DTR 2 17 18 RI 2
GND 19 20 N/C

RS-422 Mode

N/C 1 2 N/C
TXD+ 1 3 4 TXD- 1
GND 5 6 RXD- 1
RXD+ 1 7 8 N/C
GND 9 10 N/C
N/C 11 12 N/C
TXD+ 2 13 14 TXD- 2
GND 15 16 RXD- 2
RXD+ 2 17 18 N/C
GND 19 20 N/C

RS-485 Mode

N/C 1 2 N/C
TX/RX+ 1 3 4 TX/RX- 1
GND 5 6 N/C
N/C 7 8 N/C
GND 9 10 N/C
N/C 11 12 N/C
TX/RX + 2 13 14 TX/RX- 2
GND 15 16 N/C
N/C 17 18 N/C
GND 19 20 N/C

Emerald-MM Block Diagram


Serial Ports
Number of serial ports 4
Protocol RS-232, RS-422, RS-485 (jumper selected)
Maximum baud rate 115kbps standard version
460.8kbps available (EMM-HS-XT)
Communications parameters 5, 6, 7, or 8 data bits
Even, odd, or no parity
Short circuit protection All outputs protected against continuous short circuit
RS-232 mode:
Input impedance 3KΩ minimum
Input voltage swing ±30V maximum
Output voltage swing ±5V min, ±7V typical
RS-422, RS-485 modes:
Differential -0.2V min, +0.2V max input threshold
Input impedance 12KΩ minimum
Input current +1.0µA max (VIN = 12V)
-0.8µA max (VIN = -7V)
Differential output voltage 2.0V min (RL=50Ω)
High/low states differential output voltage symmetry 0.2V maximum
I/O header 2 20-position (2x10) .025" square pin header on .1" center;
Headers mate with standard ribbon cable (IDC) connectors
Dimensions 3.55" x 3.775"
Power supply +5VDC ±10%
Current consumption 80mA typical, all outputs unloaded
Operating temperature -40°C to +85°C Extended
Operating humidity 5% to 95% noncondensing
PC/104 bus 8-bit and 16-bit bus headers are installed
Weight 2.6oz/74g
MTBF EMM-4M-XT 555,428 hours
RoHS Compliant
4 serial ports
Jumper configurable RS-232, RS-422, RS-485 on all ports
Flexible address and interrupt selection
Full interrupt sharing capability
Interrupt status register for Windows NT
Dual 20-pin I/O headers (2 ports per header)
+5V only power supply
-40°C to +85°C extended temperature operation
Customers who use this product also use:
2-port DB9 Serial Cable

This product can be customized and ruggedized. Click here for more information.
See Emerald-MM-4M 4-Port Serial Module Technical Resources
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Emerald-MM-4M Datasheet
(.pdf, 112.5 kb)
Emerald-MM-4M User Manual
(.pdf, 311.5 kb)

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Emerald-MM-4M 4-Port Serial Module
available models:
Emerald-MM 4-ch RS-232/422/485, Extended Temperature
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Cables and accessories
available models:
Serial port cable, 2x DB9M to 2x10 .1" socket (uses 2)
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VDC 2006 Platinum Vendor Award