CH1787 데이터 시트보기 (PDF) - Cermetek Microelectronics

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CH1787

Small Footprint Hardware Controllable 2400bps Modem

Cermetek Microelectronics 

Cermetek Microelectronics, Inc.

Table 3. CH1787 AT Command Set Summary.

Basic

Commands Function

AT

Attention Code

A

Answer Command

A/

Repeat Last Command

*Bn

Communications Standard Option

D

Dial Command

*E

Off-Line Character Echo Option

Hn

Switch Hook Control Option

*Ln

Speaker Volume Option

*Mn

Speaker Control Option

On

On-Lone Command

P

Pulse Dial

*Qn

Result Code Display Option

Sn

Select an S Register

Sn=

Write to an S Register

Sn?

Read an S Register

*Vn

Result Code From Option

*Xn

Result Code Set/Call Progress Option

+++

Escape Code Sequence

,

Pause

?

Returns Last Addressed S Register

*Yn

Long Space Disconnect Option

Fn

On-Line Echo Character Option

Z

Reset

Ampersand

Commands Function

*&Dn Data Terminal Ready Option

&F

Load Factory Defaults

*&Gn Guard Tone Option

*&Pn Make to Break Ratio Selection

*&Sn Data Set Ready Option

&Tn

Test Command Option

&V

View Active Configuration

*&Wn Store Active Profile

*Yn

Recall Active Profile

*&Zn

Store Telephone Numbers

*&Cn Not Supported

Percent

Commands Function

%Dn

DTMF Attenuation

%J

Load Secondary Factory Defaults

*= Commands that can be stored in NVRAM.

NOTE: Refer to Cermetek Publication AT Commands

and S-Registers for a detailed discussion of

parameters in Table 2 and 3.

Two of these lines are all that are required for proper

CH1787 operation: TXD, RXD and DTR. The modem

is controlled by sending it serial commands over TXD

and can be monitored by serial status messages

returned on RXD.

All other serial interface lines may be utilized for the

convenience of your application but are not required by

the modem. Unused outputs (form modem) should be

CH1787 Small Footprint Hardware Controllable 2400bps Modem

left unconnected. Unused inputs should be tied to the

proper logic level. See pin description.

Figure 5. Speaker Control. Circuit allows call

progress monitoring.

PHONE LINE CONNECTION GUIDELINES

1. The mounting of CH1787 in the final assembly

must be made so that it is isolated from exposure to

any hazardous voltages within the assembly.

Adequate separation and restraint of cables and

cords must be provided.

2. The circuitry from the CH1787 to the telephone line

interface must be provided in wiring that carries no

other circuitry than that specifically allowed in the

rules (such as A and A1 leads).

3. Connection to phone line should be made through

an RJ-11 jack.

4. Traces from the modem’s RING and TIP pins to the

RJ-11 jack must exceed 0.1 inch spacing to one

another and 0.2 inch spacing to all other traces.

The traces should have a nominal width of 0.020

inches or greater.

5. The RING and TIP traces should be as short as

possible and oriented to prevent coupling other

high speed or high frequency signals onto the host

circuit card.

6. No additional circuitry other than that shown in the

following Figure may be connected between the

modem module and RJ-11 jack.

7. The CH1787, the RJ-11 jack, the interfacing

circuitry and traces in between, must be mounted

on a circuit board with a 94 V-0 flammability rating.

8. The supplied FCC registration label must be

applied visibly on the outside of the host product.

2002 Cermetek Microelectronics, Inc.

Page 8

Document No. 607-0002 Revision B (03/02)

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