Symbol MiniScan MS-120X, Integration Manual

Page: 72 / 410

5-4
MS-120X and MS-220X Integration Guide
Application Notes
TTL RS-232
Standard RS-232 voltage levels typically range b12V and -12V to ensure
adequate noise rejection over long distances. Devices which support TTL level RS-232
signaling typically drive signals between 0V and +5V. Extensive testing has shown that TTL
levels are interpreted correctly by the majority of standard RS-232 hosts over cable
distances of six feet or less, even in extreme conditions.
Multi-interface Miniscan Plus products fall into the TTL RS-232 device category. All
standard RS-232 cables available from Symbol for the Miniscan Plus family measure six
feet or less, and should not present a problem. If a particular host does not support TTL
levels, a separate conversion cable is available (25-62186-xx) which contains electronics
to adapt the TTL levels of a multi-interface Miniscan Plus into standard RS-232 levels.
USB Warning - Potential Host Side Issues
The Universal Serial Bus provides a smart plug-and-play interface for easy integration. In
USB communication, the root hub located on the host controls all traffic. USB hosts in
general react poorly in certain harsh environments compared to traditional host interfaces
such as RS-232. These environments include areas with high ESD levels or situations in
which the system is subject to Electrical Fast Transients (EFT).
8 RTS/SYN_DAT I/O RS232 Mode : Request-to-send handshaking output line, used only
in conjunction with the CTS line. Optionally used by the scanner to
signal another device that data is available to send.
USB Mode : Synapse Data line. Signal is used to transmit data to
and from a Symbol Synapse host.
9 Beeper/
Download I/O During normal operation this signal functions as an external beeper
drive line. This signal can sink 50mA of current to drive an external
beeper, and is normally pulled up. This signal is also used to begin
Flash Download operation when grounded externally during power
up.
Table 5-2. MS-2207 Electrical Interface (Continued)
Pin
No.
Pin Name Type* Function
*I = Input O = Output