Synway Information Engineering Co., Ltd
Chapter 1 Overview
The CTI series SHT-2B/USB and SHT-4B/USB are the voice boxes using analog telephone lines
and USB1.1 interface. With various functional modules configured in a different way, they can
work as virtual, station or trunk phones to accept incoming calls.
1.1 Functions
zEquipped with an audio amplifier, a speaker (able to simulate ringing) and an audio
output port to directly drive the speaker in headset or phone handset.
zDetects the ringing current on the trunk channel, the pickup/hangup behavior on the
station channel, the phone line voltage and the polarity reversal. Transmits the ringing
current.
zThe trunk and station channels are connected directly during power outage, which
improves the system security to a great extent.
zAutomatically checks the USB voice box to determine the model and number of modules
installed on it.
zUses SPECDial - a professional driver algorithm - to perform a complete automatic dial
process through analog lines, accurately identify called-party statuses and precisely
determine whether the answering is from the subscriber, the answering machine or the
fax machine.
zCalling party info (Caller ID) detection/transmission, DTMF and FSK support; adopts the
echo cancellation algorithm conforming to the telecom standard; supports the Barge-in
feature for IP phone application and speech recognition.
zSupports signal modulation and demodulation, enabling communication of FSK signals
with such information terminals as PDA and information phones.
zSupports simultaneous full-duplex recording and playback on 4 channels, each with a
different format (CCITT A/μ-Law 64kbps or IMA ADPCM 32kbps)
zProgrammable tone analyzer detects all kinds of tones on analog channels
zAutomatic Gain Control (AGC) support in recording operation
zAdaptive echo cancellation
SHT-2B/USB, SHT-4B/USB Hardware Manual (Version 1.0) Page 1
