Specifications

Cinterion
®
ALAS66A Hardware Interface Overview
2.1 Application Interface
33
 ALAS66A_HIO_v01.000a 2019-02-26
Confidential / Released
Page 18 of 51
2.1.2 Serial Interface ASC0
ALAS66A offers a 4-wire (8-wire prepared) (plus GND) unbalanced, asynchronous interface
ASC0 conforming to ITU-T V.24 protocol DCE signaling. The electrical characteristics do not
comply with ITU-T V.28. The significant levels are 0V (for low data bit or active state) and 1.8V
(for high data bit or inactive state).
ALAS66A is designed for use as a DCE. Based on the conventions for DCE-DTE connections
it communicates with the customer application (DTE) using the following signals:
• Port TXD @ application sends data to the module’s TXD0 signal line
• Port RXD @ application receives data from the module’s RXD0 signal line
Figure 3: Serial interface ASC0
Features:
• Includes the data lines TXD0 and RXD0, the status lines RTS0 and CTS0. The modem con-
trol lines DTR0, DSR0, DCD0 and RING0 are not yet implemented.
• The RING0 signal serves to indicate incoming calls and other types of URCs (Unsolicited
Result Code). It can also be used to send pulses to the host application, for example to
wake up the application from power saving state. Not yet implemented.
• Configured for 8 data bits, no parity and 1 stop bit.
• ASC0 can be operated at fixed bit rates from 115,200 to 921,600bps.
• Supports RTS0/CTS0 hardware flow control.
Note: If the ASC0 serial interface is the application’s only interface, it is suggested to connect
test points on the USB signal lines as a potential tracing possibility.