General; Connections And Display Elements - Relay MOD002 User Manual

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M-Bus – Modem Manual

1. General

The system for M-Bus data transmission through an analog telephone line comprises a
modem for the PC and a modem for the level converter from RS232C to M-Bus. It allows
remote transmission that complies with the data security level from EN1434–3 and the new
EN13757-2 in conformance with standards, especially the transmission of the even parity bit.
The modem may also be used in standard mode for standardized data transmissions (incl.
fax) with a data communications speed of up to 33600 baud.

2. Connections and Display Elements

The M-Bus modem contains nine yellow LEDs on the front to indicate the operating states
and the DTE interface signals (RS-232C). The power LED indicates the ready state of the
modem. The RING LED signals (synchronized) the bell character for an incoming call. The
DCD LED indicates that a data communications connection has been established with a
remote station modem. RxD and TxD LED change their brightness in synchronization with
incoming and outgoing data. Please refer to the modem manual for more detailed information
on the other LEDs.
M-Bus - MODEM 31.01.07, Version 2.0 Seite / Page 9