Technics MT5634SMI-34 manual Pin Configurations, Pin Descriptions for Serial SocketModem Devices

Chapter 2 – Mechanical Specifications

Pin Configurations

The MT5634SMI SocketModem uses a 20-pin interface to provide an on-board DAA with tip and ring connections, audio circuit for call-progress monitoring, LED driver for call status annunciation, and serial interface.

Figure 2–2. Serial SocketModems Pins

Pin Descriptions for Serial SocketModem Devices

Pin # Signal Name I/O Type

Description

26	DGND		Digital Ground
33	–RTS	I	Request to Send. RTS signal is used for hardware flow control.
34	–RXD	O	Received Data. The modem uses the RXD line to send data received from
			the telephone line to the DTE and to send modem responses to the DTE.
			During command mode, –RXD data presents the modem responses to the
			DTE. Modem responses take priority over incoming data when the two signals
			are in competition for –RXD. When no data is transmitted, the signal is held in
			mark condition.
35	–TXD	I	Transmitted Data. The DTE uses the –TXD line to send data to the modem
			for transmission over the telephone line or to transmit commands to the
			modem. The DTE should hold this circuit in the mark state when no data is
			being transmitted or during intervals between characters.
36	–RI	O	Ring Indicate. –RI output ON (low) indicates the presence of an ON segment
			of a ring signal on the telephone line. The modem will no go off-hook when –RI
			is active; the modem waits for –RI to go inactive before going off-hook.
37	–DSR	O	Data Set Ready. –DSR indicates modem status to the DTE. –DSR OFF
			(high) indicates that the DTE is to disregard all signals appearing on the
			interchange circuits except Ring Indicator (–RI). It reflects the status of the
			local data set and does not indicate an actual link with any remote data
			equipment.
38	–CTS	O	Clear To Send. –CTS is controlled by the modem to indicate whether or not
			the modem is ready to transmit data. –CTS ON indicates to the DTE that
			signals presented on TXD will be transmitted to the telephone line. –CTS OFF

SocketModem Global MT5634SMI Developer’s Guide 11