ERICSSON EH238 ServTeleph

SERVICE: Telephone

Ericsson Handheld Telephone 1341-B

SERVICE: Telephone

2

Contents

SERVICE: Telephone

Connectors and Signals

Connector J1 ____________ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __4

Disassembly

Reassembly______________________ __ __ __ __ __ __ __ __ __ __ __ __7
Changing the Circuit Board _________________________________7

Fault Finding and Alignment
Sequence of Adjustments

____________ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __6

____________ ______________ ____4

____________ ______________8

____________ ______________ __9

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SERVICE: Telephone

Connectors and Signals

The location of the logic board connectors and a description of the respective
signal names will follow below.

Connector J1

1 ATMS
2 PWSRC
3 LSPCTRL
4 AGND
5 AFMS
6 SWDC5
7 ICTRL
8 DGND
9 VPPFLASH
10 HOOK
11 DTMS
12 DFMS
13 ONSRQ
14 DCIN

SM1341EN/CONJ1.GEM

Table 1: Connector J1

Pin Signal In/Out Function

1 ATMS In Audio To Mobile Station

Sensitivity: 50 mV,
referred to +/-2.3 kHz dev.

Input imp. 10 kΩ/ nF

2 PWRSRC In Power source

Indicates external power supply
Log. "1": External po wer supply
Log. "0": Battery

3 LSPCTRL Out Loudspeaker control

Handsfree loudspeaker control
Log. "1": Speaker ON
Log. "0": Speaker OFF

4 AGND Analog ground

Signal ground 0 V
Return lead for pi n s 5 an d 1

4

Pin Signal In/Out Function

SERVICE: Telephone

5

6

7

8

9

10

AFMS

SWDC5

ICTRL

DGND

VPPFLASH

HOOK

Out Audio From Mobile Station

Output 307 mV, referred to 5.7 kHz dev.
(varies with volume)

Output imp. < 1 k

Out Logic control signal (4.8 V) for external

units.
Max. current 10 mA

Out Control of external supply current.

Log. "1": Supply 700 mA
Log. "0": Supply 30 mA

Digital ground

In Disconnects internal watchdog during

test and supplies programming voltage to
flash memory
Open: normal mode
5 V: test mode
12V: programming voltage

In External Handsfree present

Log. "1": External HF present
Log. "0": No external Handsfree

Ω

11

12

13

14

DTMS

DFMS

ONSRQ

DCIN

In Data To Mobile Station

Asynchrono u s se ria l tr an sf er :
8 bits, 600 bits/s

Input impedance 100 kΩ/ nF
Log. "1": 4.8 V
Log. "0": 0.5 V

Out Data From Mobile Station

Asynchrono u s se ria l tr an sf er :
8 bits, 600 bits/s
Log. "1": 4.8 V
Log. "0": 0.5 V

In ON and Service Request signal

If momentarily connected to GND causes
telephone to shift between ON and OFF
state

In Supply to telephone

Min. 5.3 V; max. 8.5 V
Nominal 6.8 V, max. 1 A

5