Network Device User's Guide Omni 56K Plus Series

Omni 56K Plus Series User’s Guide
2-10 Specifications and Function Description
 Before the security type or level can be changed, the modem
requires the supervisor password.
For type2 security, the remote site will be prompted to enter the user password. A maximum of 3 tries
in 40 seconds is allowed. If a correct password is not entered within this time limit, the line will be
disconnected. If the remote site is to enter the call-back number, it will be prompted to do so.
2.6 Fax function
2.6.1 Fax Physical Layer Protocol
Table 2-6 Fax Physical Layer Capacity
STANDARD BIT RATE [BPS] BAUD RATE [BAUD] MODULATION CARRIER FREQUENCY [HZ]
V.17 14400-7200 2400 TCM 1800
V.29 9600-4800 2400 QAM/DPSK 1700
V.27ter 4800-2400 1600/1200 PSK/DPSK 1800
V.21 300 300 FSK
2.6.2 EIA Class 1/Class 2/Class 2.0 Command Set
Please refer to Fax Command Set in Chapter 4.
2.6.3 ITU-T T.30 Fax Protocol
The ITU-T T.30 fax protocol is known as the G3 fax handshake signals and procedures. The modem
takes full control of this protocol - initiating and terminating fax calls, managing the communication
session, and transporting the image data. Therefore, the modem relieves the computer fax software of
the T.30 protocol handling.
You modem allows for fax speeds up to 14400 bps when transmitting to a fax machine which
complies with the V.17 fax standard. Speeds will fall back to 12000, 9600, or 7200 bps in poor line
conditions. When connecting to a G3 fax device, your modem allows for fax speeds up to 9600 bps
and will automatically fall back to 7200, 4800, and 2400 bps if the line quality is poor.
2.7 Voice Function
Voice capability stands for the modem’s ability to digitize incoming voice messages, which the
computer stores and forwards. It also means that the modem can playback the recorded digitized voice
on line for a message announcement.
2.7.1 Voice IS-101 Command Set
Please refer to the Voice command sets in Chapter 4.
2.7.2 4-bit Voice Data Compression
The main issue in the digitized voice mode is the amount of storage required. A relatively simple
ADPCM algorithm can reduce the speech data rate to half the rate and maintain about the same voice