User Manual

Cinterion
®
ELS31-V/ELS51-V Hardware Interface Overview
2.1 Application Interface
17
ELS31-V_ELS51-V_HIO_v00.502 2015-12-07
Confidential / Preliminary
Page 7 of 35
2.1.2 Serial Interface ASC0
ELS31-V / ELS51-V offers an 8-wire unbalanced, asynchronous modem interface ASC0 con-
forming to ITU-T V.24 protocol DCE signalling. 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).
ELS31-V / ELS51-V 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 and, in addition,
the modem control lines DTR0, DSR0, DCD0 and RING0.
Configured for 8 data bits, no parity and 1 stop bit.
ASC0 can be operated at fixed bit rates from 1200bps up to 921600bps.
Supports RTS0/CTS0 hardware flow control. Communication is possible by using only RXD
and TXD lines, if RTS0 is pulled low.
Wake up from SLEEP mode by RTS0 activation (high to low transition).