Interface Characteristics - Motorola MVME1603 Installation And Use Manual

EIA-232-D Connections
Pin
Number
C
15
16
17
18, 19
20
21
22
23
24
25

Interface Characteristics

C-4
Table C-2. EIA-232-D Interconnect Signals (Continued)
Signal
Mnemonic
Transmit Clock (DCE). Output from modem to terminal; clocks data from the terminal
TxC
to the modem.
Not used.
Receive Clock. Output from terminal to modem; clocks input data from the terminal to
RxC
the modem.
Not used.
Data Terminal Ready. Input to modem from terminal; indicates that the terminal is
DTR
ready to send or receive data.
Not used.
Ring Indicator. Output from modem to terminal; indicates that an incoming call is
RI present. The terminal causes the modem to answer the phone by carrying DTR true
while RI is active..
Not used.
TxC Transmit Clock (DTE). Input to modem from terminal; same function as TxC on pin 15.
Busy. Input to modem from terminal; a positive EIA signal applied to this pin causes the
BSY
modem to go off-hook and make the associated phone busy.
Notes
1. A high EIA-232-D signal level is +3 to +15 volts. A low level
is −3 to −15 volts. Connecting units in parallel may produce out-
of-range voltages and is contrary to specifications.
2. The EIA-232-D interface is intended to connect a terminal to a
modem. When computers are connected without modems, one
computer must be configured as a modem and the other as a
terminal.
The EIA-232-D interface standard specifies all parameters for serial binary
data interchange between DTE and DCE devices using unbalanced lines.
EIA-232-D transmitter and receiver parameters applicable to the
MVME1603/MVME1604 are listed in the following tables.
Signal Name and Description