XECOM (4) XE1486L
XE1486L Pin Descriptions
PIN NAME DESCRIPTION
1 Ring Ring provides half of the two-wire connection to the telephone network, RJ-11 Pin 4.
A 1500 volt barrier isolates Ring from all other circuits. This isolation must be preserved throughout the system. The battery voltage on Ring may be positive or negative
with respect to Tip.
2 Tip Tip provides half of the two-wire connection to the telephone network, RJ-11 Pin 3. A
1500 volt barrier isolates Tip from all other circuits. This isolation must be preserved
throughout the system. The battery voltage on Tip may be positive or negative with respect to Ring.
3, 4 Not Used No Connection should be made to these pins.
5 SPK SPK provides the audio output to a speaker. Speaker output is controlled by the ATL
and ATM commands. The input impedance to the speaker driver must be greater than
300 ohms.
6-9 N/C No Connection
10 TXD TXD provides serial data input from the host. A logic high represents a "Mark" and a
low represents a "Space".
11 RXD RXD provides serial data output to the host. A logic high represents a "Mark" and a
low represents a "Space".
12 /V-D The Voice-Data output can be used to drive an external relay for switching between the
modem and handset connected to the same telephone line.
13 /DTR Data Terminal Ready is an active low input to the modem. The AT&D command sets
the function of DTR.
14 /DSR Data Set Ready is an active low output from the modem. Its operation is determined by
the AT&S command.
15 /RI Ring Indicator is an active low output which marks the presence of a ring on the line.
16 /CTS The XE1486L uses Clear to Send for hardware flow control. With hardware flow con-
trol active the modem raises \CTS to signal the host that the modem's transmit data
buffer is nearly full. When the buffer empties, the modem reactivates CTS.
17 /DCD Data Carrier Detect goes low to indicate receipt of a valid incoming carrier. The
AT&C1 command enables the carrier detect function.
18 N/C No Connection
19 VCC VCC provides the +5 volt power required by the modem.
20 GND Ground provides the common reference for the XE1486L.
21 RST This active high input causes a hardware reset in the XE1486L. The reset pulse must be held
high for at least 10 milliseconds to correctly reset the modem.
22 RTS The modem uses Request to Send for hardware flow control. The modem stops sending data to
the host when the hosts raises /RTS. The modem resumes transferring data to the host when the
host activates /RTS