Manuale d’uso / di manutenzione del prodotto B1474 del fabbricante Barnett Engineering
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RA DIO MO DEM B1474 OP ER A TION MAN UAL April, 1998 Manual Revision 4.1 (for Version 2.1 Hardware).
TA BLE OF CON TENTS FCC RE QUIRE MENTS ................... 2 1 IN TRO DUC TION ...................... 3 2 SPEC I FI CA TIONS ..................... 5 3 NO TA TION ........................ 7 4 OP ER A TION ........................ 8 5 SETUP PRO CE DURES .
FCC RE QUIRE MENTS This equipment generates, uses, and can radiate radio frequency energy and, if not used in accordance with the instruction manual, may cause interference to radio communications.
1 IN TRO DUC TION The B1474 Radio Modem provides a reliable method of sending 1200 baud data signals over radio or cable facilities. Digital information is converted to tone format for transmission over the communication channel. Received tones are converted back to RS232 digital format.
In di ca tors Modem status condition is indicated by front panel LEDs. The LEDs may be disabled to conserve power. B1474 BARNETT EN GI NEERING LTD. PAGE 4.
2 SPEC I FI CA TIONS GEN ERAL Trans mis sion Rate: 1200 Baud (Bell 202 sig naling) or V.23 if fac tory in stalled Trans mis sion For mat: 8 data bits, no par ity, 1 stop bit if mo dem buff er ing is se lected; oth er wise trans par ent Power Re quire ment: Op er ates from 12 to 30 VDC .
PTT Drop De lay: 0, 10, 20, 50, 75, 100 or 250 msec. Keeps trans mit ter keyed long enough to en sure squelch tail noise does n’t in ter fere with data at the re ceiv ing ter mi nal. Hand shak ing: Spec ifies the type of flow con trol used. 2/4 Wire: Se lects 2 or 4 wire ca ble op er a tion.
3 NO TA TION Throughout this manual, abbreviations will be used. These abbreviations are explained here for clarity. CD Carrier Detect COS Carrier Operated Switch CTS Clear To Send DCE Data Communicat.
4 OP ER A TION The B1474 operates from 12 to 30 VDC to provide an interface between two computer devices and the communications channel. In the descriptions below it is assumed that the sending device uses a DCE configuration.
B1474 BARNETT EN GI NEERING LTD. PAGE 9 FIGURE 1 MODEM TIMING USING RTS AND CTS.
Soft ware Hand shak ing Using XON / XOFF Basic operation and timing using XON / XOFF software handshaking are as follows: • The send ing com puter be gins send ing data.
– checks the chan nel, if this fea ture is en abled. If the chan nel is free, it as serts its PTT to power up the ra dio’s trans mit ter. If the chan nel is busy, it buff ers the re ceived data un ti l the chan nel be comes free. – pres ents MARK tone (car rier) onto the chan nel.
5 SETUP PRO CE DURES The semiconductors can be damaged by static discharge. Proper handling procedures must be followed . Do not touch any of the devices inside the modem, and work only in a static free, clean, and dry environment. (1) Re move The Top Cover Remove the two center screws on the top cover of the modem to release it from the base.
GND (Chassis) Pin 1 TXD Pin 2 RXD Pin 3 RTS Pin 4 (connect only if using hardware handshaking) CTS Pin 5 (connect only if using hardware handshaking) GND (Signal) Pin 7 CD Pin 8 The cable and housing on the DB-25S socket must be shielded to conform to FCC, part 15-J/A standard s for emissions.
Adjust R12 so that the modem waits when the channel is busy, and transmits when the channel is free. When the BUSY light is ON, the modem is waiting for the channel. To disable this feature, leave P1-9 unconnected and SW1.9 OFF. If Option 002 trunking software is used, set SW1.
To operate full duplex, leave SW2.8 OFF. To operate half duplex, set switch SW2.8 ON. If a 2 wire circuit is used, the modem will only operate half duplex. RTS Con trol SW3.1, when ON, will assert RTS continuously. This causes PTT to be asserted and transmit tones to be generated.
6 IN DI CA TORS The LED indicators on the front case are used to indicate modem status: RUN Power is on the modem. BUSY The modem is waiting to transmit but is held back by the squelch detector. RTS Request To Send from the computer is present or characters have been re ceived into the buffer.
B1474 BARNETT EN GI NEERING LTD. PAGE 17 7 CONFIGURATION RTS/ CTS DE LAY 20 X 50 3 msec 2 35 X 4 LEDS OFF X LEDS ON 1 LED CON TROL SWITCH 1 PTT DROP DE LAY 200 X 300 X X X 500 X X 1000 X X X 100 X X X.
B1474 BARNETT EN GI NEERING LTD. PAGE 18 BUFFER USE RTS/ CTS CON TROL X USE BUFFER 2 SWITCH 3 RTS ON 4 WIRE CA BLE X 2 WIRE CA BLE 4 RTS ON EX TER NAL RTS X RTS ON AT ALL TIMES 1 X 3.
B1474 BARNETT EN GI NEERING LTD. PAGE 19 +V 8 INPUT VO LT AGE GROUND TX WL TX WL TX RADIO 7 6 5 4 3 9 1 PIN SYMBOL DESCRIPTION GND 2 RX RADIO RX WL RX WL SQL PTT TRANSMIT OUTPU T , SINGLE ENDED TRANSM.
9 BOARD L AY OUT B1474 BARNETT EN GI NEERING LTD. PAGE 20.
Barnett En gi neering Prod uct War ranty WARRANTY STATEMENT Barnett Engineering Ltd . warrants that all equipment supplied shall be free from defects in material or workmanship at the time of delivery. Such warranty shall extend from the time of delivery for a period of one year.
11 AP PEN DIX A - OP ER A TION WITH A GE MARC V TRUNKING SYS TEM When ordered with the Option 002 trunking software, the B1474 will handle the special timing and control requirements of a GE Marc V trunking system. The following sections describe the connections to a trunking radio, and the slightly different operation of the radio modem.
B1474 BARNETT EN GI NEERING LTD. PAGE 23 FIGURE 2 MODEM TIMING FOR A GE MARC V TRUNKING SYSTEM USING RTS/ CTS HANDSHAKING.
Soft ware Hand shak ing Using XON / XOFF Basic operation and timing using XON / XOFF software handshaking in a trunking system is as follows: • The send ing com puter be gins send ing data. The for mat must be 8 data bits, no par ity, 1 stop bit. • Upon de tect ing data, the send ing mo dem per forms the fol low ing: – checks the chan nel.
No Hand shak ing Basic operation and timing with data buffering (no handshaking) in a trunking system is as follows: • The send ing com puter be gins send ing data.
Un punto importante, dopo l’acquisto del dispositivo (o anche prima di acquisto) è quello di leggere il manuale. Dobbiamo farlo per diversi motivi semplici:
Se non hai ancora comprato il Barnett Engineering B1474 è un buon momento per familiarizzare con i dati di base del prodotto. Prime consultare le pagine iniziali del manuale d’uso, che si trova al di sopra. Dovresti trovare lì i dati tecnici più importanti del Barnett Engineering B1474 - in questo modo è possibile verificare se l’apparecchio soddisfa le tue esigenze. Esplorando le pagine segenti del manuali d’uso Barnett Engineering B1474 imparerai tutte le caratteristiche del prodotto e le informazioni sul suo funzionamento. Le informazioni sul Barnett Engineering B1474 ti aiuteranno sicuramente a prendere una decisione relativa all’acquisto.
In una situazione in cui hai già il Barnett Engineering B1474, ma non hai ancora letto il manuale d’uso, dovresti farlo per le ragioni sopra descritte. Saprai quindi se hai correttamente usato le funzioni disponibili, e se hai commesso errori che possono ridurre la durata di vita del Barnett Engineering B1474.
Tuttavia, uno dei ruoli più importanti per l’utente svolti dal manuale d’uso è quello di aiutare a risolvere i problemi con il Barnett Engineering B1474. Quasi sempre, ci troverai Troubleshooting, cioè i guasti più frequenti e malfunzionamenti del dispositivo Barnett Engineering B1474 insieme con le istruzioni su come risolverli. Anche se non si riesci a risolvere il problema, il manuale d’uso ti mostrerà il percorso di ulteriori procedimenti – il contatto con il centro servizio clienti o il servizio più vicino.
