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 8 of 35
2.1.3 Serial Interface ASC1 (ELS51-V Only)
ELS51-V provides a 4-wire unbalanced, asynchronous modem interface ASC1 conforming 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). With ELS31-V, ASC1 can only be used as data interface.
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 module’s TXD1 signal line
Port RXD @ application receives data from the module’s RXD1 signal line
Figure 4: Serial interface ASC1
Features
Includes only the data lines TXD1 and RXD1 plus RTS1 and CTS1 for hardware hand-
shake.
On ASC1 no RING line is available.
Configured for 8 data bits, no parity and 1 or 2 stop bits.
ASC1 can be operated at fixed bit rates from 1,200 bps to 921600 bps.
Supports RTS1/CTS1 hardware flow control. Communication is possible by using only RXD
and TXD lines, if RTS1 is pulled low.
Wake up from SLEEP mode by RTS0 activation (high to low transition).