Technics MT5634SMI-92 manual Tip Signal from Telco, Ring Signal from Telco, Active High DCD status

			Chapter 2 – Mechanical Specifications
			indicates to the DTE that it should not transfer data across the interface on
			TXD.
39	–DCD	O	Data Carrier Detect. –DCD output is ON (low) when a carrier is detected on
			the telephone line or OFF (high) when carrier is not detected.
40	–DTR	I	Data Terminal Ready (Active Low). The –DTR input is turned ON (low) by
			the DTE when the DTE is ready to transmit or receive data. –DTR ON
			prepares the modem to be connected to the telephone line, and, once
			connected, maintains the connection. –DTR OFF places the modem in the
			disconnect state.
41	DGND	GND
61	VCC	PWR	+5V or 3.3V Supply (depends upon model).
63	AGND	GND	Analog Ground. Analog ground is tied common with DGND on the
			SocketModem. To minimize potential ground noise issues, connect audio
			circuit return to AGND.
64	SPKR		Speaker Output. SPKR is a single ended-output. SPKR is tied directly to the
			CODEC.

LED driver outputs are open-drain inverter-driven (74HCT05) lines with 1.5K ohms pull-up resistors. Max output current 25 mA.

1	Tip	I/O	Tip Signal from Telco.
2	Ring	I/O	Ring Signal from Telco.
24	–RESET	I	Modem Reset (with weak pull-up). The active low –RESET input resets the
			SocketModem logic and returns the AT command set to the original factory defau
			values or to "stored values" in NVRAM. –RESET is tied to VCC through a 400ms
			time constant circuit for "Power-on-Reset" functionality. The modem is ready to
			accept commands within 6.5 seconds of power-on or reset. Reset must be asser
			for 300 ns.
29	DCDIND	O	Active High DCD status.
30	RXIND	O	Active High RDX status
31	DTRIND	O	Active High DTR status
32	TXDIND	O	Active High TXD status

SocketModem Global MT5634SMI Developer’s Guide 12