Connecting Data Circuit-terminating Equipment (DCE) (RS232)

General

Data Circuit-terminating Equipment (DCE) is the term used to describe devices such as modems.

For a DCE type device, the RTS and CTS pins are connected directly (not crossed).

All data circuit-terminating equipments are connected to a BMX P34 1000/2000/2010/20102/2020 processor by a serial direct cable using an RS232 physical link.

NOTE: The differences between DCE and DTE connections are largely in the plugs and the signal direction of the pins (input or output). For example, a desktop PC is termed as a DTE device while a modem is termed as a DCE device.

Modem Characteristics

M340 CPUs work with most modems on the market. To connect a modem to the serial port of a BMX P34 1000/2000/2010/20102/2020 processor, the modem must have the following characteristics:

Support 10 or 11 bits per character if the terminal port is used in Modbus Serial:
- 7 or 8 data bits
- 1 or 2 stop bits
- Odd, even or no parity
Operate without a data carrier check.

Connecting Data Circuit-terminating Equipment

The illustration below shows how a modem is connected to a BMX P34 2010 processor:

NOTE: In Modbus Serial, the waiting time must be between 100 and 250 ms.

RS 232 Serial Direct Cable

The TCS MCN 3M4M3S2 serial direct cable has two connectors:

RJ45 male,
Nine-pin SUB-D male.

The illustration below shows the pin assignment for a TCS MCN 3M4M3S2 serial direct cable:

Connecting Cables and Accessories

The table below shows the product references of the cables and adapters to be used according to the serial connector used by the Data Circuit-terminating Equipment:

Serial Connector for Data Circuit-terminating Equipment	Wiring
Nine-pin SUB-D female connector	TCS MCN 3M4M3S2 cable
25-pin SUB-D female connector	TCS MCN 3M4M3S2 cable TSX CTC 09 adapter