73D2248A/2348A

MNP5, V.42bis Datacom

Modem Device Set

2

FUNCTIONAL DESCRIPTION

The 73D2248A/2348A device set forms the basis for

an international modem design incorporating the

most

advanced

error

control

and

compression

algorithms. The set consists of two chips, the

73K224L (73K324L) modem and the 73M2910

controller. Customization of the controller is one of

the features of this device set; software modules

allow the modem vendor to provide a range of

features from a standard hardware platform.

The 73K224L (73K324L) provides the QAM, PSK

and FSK modulator and demodulator functions, call

progress and handshake tone monitors, test modes

and a tone generator capable of producing DTMF,

answer and CCITT guardtones.

This single-chip

modem supports the V.22bis, V.22, V.21 and Bell

103/CCITT V.23/212A operating protocols in both

sync and async modes.

Low level functions of the

controller provide for automatic detection of DTE

speed,

auto-dial,

auto-answer,

handshake

with

fallback and call progress detection.

The 73M2910 controller handles both the low level

modem functions as well as protocol negotiation and

protocol operation.

Software modules can be

chosen to provide the desired protocols for product

customization and differentiation. In addition, the

“AT” command set source code will be available for

those

desiring

to

provide

unique

or

country

dependent features.

Basic capabilities of the modem are those found in

the 73K224L (73K324L) single-chip modem and are

listed in the separate 73K224L (73K324L) data

sheet.

AUTOMATIC HANDSHAKE

The 73D2248A/2348A will automatically perform a

complete handshake with a called or calling modem

and enter the data transfer mode. After the link

between the two modems has been established, the

modems may remain in the normal data mode or

negotiate a link which has error control and data

compression. Commands are provided to inform the

modem which action is appropriate.

TEST MODES

The 73D2248A/2348A device set has provisions for

three test modes: analog loopback, digital loopback

and remote digital loopback.

Analog loopback

allows data to be sent into the local modem, have it

modulated and then demodulated and returned to

the local terminal.

Digital loopback requires the

cooperation of the user at the remote end and allows

data to be sent to the remote modem, demodulated,

then remodulated and returned to the local end.

Remote digital loopback allows the same capability,

without the need for a remote operator; signals are

sent to the remote modem which perform the

switching task that a remote operator would have

done.

AT COMMAND INTERPRETER

The 73D2248A/2348A includes an AT Command

Interpreter which is a superset of the Hayes 2400

Smartmodem

™ command set. Common application

software will be able to control the modem though

this interpreter.

Additional commands have been

added to provide for control of the MNP and CCITT

V.42 modes.

NON-VOLATILE MEMORY

A serial NVRAM provides 256 bytes of storage for

configuration information and telephone numbers.