Motorola 326X V.34 EIA/TIA 232-D Modem to Computer Interface, Pin 232-D ITU Signal Definition

Interface Pinouts

Introduction

This appendix describes the following:

•Interface pinouts common to all modem models, including:

—EIA/TIA 232-D, and ITU V.35 Recommendation modem-to-computer interfaces

—NC IN and OUT network control port interfaces

•326X/326X-SDC cabling requirements and diagnostics

Audio connector (DIAL LINE, LEASE/PRIVATE LINE, and PHONE) pinouts vary by country. See Appendix C for your country's pinouts.

EIA/TIA 232-D (Modem to Computer) Interface

The modem’s digital interface conforms to the EIA/TIA 232-D standard and ITU V.24, ITU V.28, and ISO 2110; the modem should be connected to a data terminal with a compatible digital interface (Table B-1). NOTE: For DTE rates greater than 38.4 kbps, refer to the “Cabling” section to determine cables and lengths.

Table B-1.

Modem/Computer Interface Connections

	EIA/TIA
Pin	232-D		ITU V.24	Signal	Definition
1	—	—	—	Not used.
2	BA		103	Transmitted Data	Digital data transmitted from the local terminal to the remote modem.
				(TXD)
3	BB		104	Received Data	Demodulated data received by the local terminal from the remote
				(RXD)	modem.
4	CA		105	Request To Send	Sent from local terminal to local modem to ready it for data
				(RTS)	transmission.
5	CB		106	Clear To Send	Passes from the local modem to the local terminal when the data port is
				(CTS)	clear to transmit data. Occurs in response to Request To Send.
6	CC		107	Data Set Ready	Indicates the local modem is ready to transmit and receive data.
				(DSR)
7	AB		102	Signal Ground	Common signal. Provides a common ground reference point for
					interface circuitry.
8	CF		109	Data Carrier	Passed from the local modem to the local DTE when an acceptable
				Detect (DCD)	carrier signal is received by the modem.
9	—	—	—	Not Used.
10	—	—	—	Not Used.
11	—	—	Answer/		Signal passed from terminal to modem to select answer/originate
				Originate Select	status. When signal is on, answer signal is selected. When signal is off,

originate signal is selected. This signal works with Mode=External.

B-2 Cabling and Interface Pinouts