CH1782A 데이터 시트보기 (PDF) - Cermetek Microelectronics

부품명

상세내역

일치하는 목록

CH1782A

Family of Ultra Small Modem Modules V.22bis-2400bps

Cermetek Microelectronics 

Cermetek Microelectronics, Inc.

Typically, voice communication would precede data

communications. For this case, the following

commands should be used to configure the CH1782A

(Refer to Figure 4) prior to using the VI port to inject

voice /tones.

Figure 4. Voice/Tone Injection Application

Drawing.

Enter: ATS0=<CR>

Result: OK

Disables auto-answer

Enter: ATS7=255<CR> Disables data-carrier time

Result: OK

out

Enter: ATS10=255<CR> Disables lost-carrier time

Result: OK

out

The following command sequences illustrate

implementation of common Voice/Tone Port

applications.

1. To answer a voice call.

(a) Enter: ATH1<CR>

Result: OK

(b) Drive V.INJ. HIGH to activate (or close) the

relay.

(c) Begin voice conversation.

2. To switch to data mode.

(a) Drive V.INJ. LOW to open the relay.

(b) At the originate modem:

Enter: ATX1<CR>

Result: OK

3. To disconnect (hang-up) a voice call or a data

call.

(a) Enter: ATH<CR>

Result: OK

4. To place a call to 1234567 using the CH1782A’s

DTMF tone generator.

(a) Enter: ATDT1234567;C0<CR>

CH1782A Family of Ultra Small Modem Modules V.22bis-2400bps

Result: OK

(b) Drive V.INJ. HIGH to close the relay.

CONNECTING TO THE HOST UART/USART

Since a modem communicates data serially and most

host products handle data in a parallel format, a UART

or USART is needed to make parallel-to-serial and

serial-to-parallel translations.

The Serial Interface Lines. The module supports a full

RS-232C/V.24 serial interface. Signal levels are TTL

rather than RS-232C level compatible, which allows you

to directly connect the modem to your host’s

UART/USART without level translating circuitry. A

complete description of each signal follows under Pin

Description.

Three of these lines must be utilized for proper modem

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. DTR must be asserted ON (LOW) for the

modem to interpret commands sent to it on TXD and

will disconnect a call id when DTR is asserted OFF

(HIGH) during a call.

All other serial interface lines may be utilized for the

convenience of your application but are not required by

the modem. Unused outputs (from modem) should be

left unconnected. Unused inputs should be tied to the

proper logic level.

International Approvals. The CH1782A can

additionally be approved for some international

telephone connections. This must be done, however,

after the modem is installed in the host product. The

entire host product must then be submitted to the

international country’s Telephone Network for approval.

Figure 5. Speaker Circuit. Allows call progress

monitoring.

2002 Cermetek Microelectronics, Inc.

Page 10

Document No. 607-0009 Revision C (01/03)

Share Link: