Cinterion
®
EMS31-V Hardware Interface Overview
2.1 Application Interface
18
EMS31_V_HIO_v00.004
2018-02-27
Confidential / Preliminary
Page 10 of 35
2.1.2
Serial Interface ASC1
EMS31-V provides a 4-wire unbalanced, asynchronous modem interface ASC1 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).
EMS31-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 3:
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 3,686,400bps.
•
Supports RTS1/CTS1 hardware flow control. Communication is possible only by respecting
hardware flow control. Otherwise, the module might disregard some data transmitted from
host.
•
Wake up from SLEEP mode by RTS1 activation.
TXD1
RXD1
RTS1
CTS1
TXD
RXD
RTS
CTS
Module (DCE)
Application (DCE)
