HP TM 11-6625-2779-14&P Accessory Equipment Supplied, Instrument Identification, BAL Modification

Section I

1-5. A noise-to-ground (Ng) function is included which permits the measurement of longitudinal noise. When making noise-to ground measurements the impedance between INPUT terminals is greater than 80 kilohms and is 100 kilohms between each terminal and ground. A HOLD function permits holding the line while noise measurements are being made. The input circuitry provides 40dB of longitudinal noise attenuation when noise-to-ground measurements are being made.

1-6. A DIAL/BAT function permits connecting a lineman's handset to the line for the purpose of dialing and at the same time connects the front panel meter to the power supply so that the battery voltage or unregulated power supply voltage can be monitored.

1-7. Jacks accepting Western Electric type 241, 309, 310, 347, and 358 plugs are provided for INPUT connections to the 3555B. Dual binding posts accept banana plugs, wires, lugs or phone tips and a pair of special connectors permit the attachment of clip leads from a lineman's handset.

1-8. The Model 3555B can be operated from either the internal 45V dry cell battery or from the ac line, 115 or 230Vac, 48Hz to 440Hz. A special device is included in the cover to automatically turn the set off when the cover is replaced. The set can also be operated from the central office battery. A jack is provided on the side of the set for this purpose.

1-9. ACCESSORY EQUIPMENT SUPPLIED.

1-10. The accessory equipment supplied with the Model 3555B is listed in Table 1-2.

Model 3555B

Table 1-2. Accessory Equipment Supplied

-hp- Part No.	Description	Quantity
8120-1348	Power Cord	1
1470-0026	Battery, 45 Volt dry cell	1
03555-26510	Test Board	1
5000-7135	Decal, 150 BAL	1

1-11. INSTRUMENT IDENTIFICATION.

1-12. Hewlett-Packard uses a two-section serial number. The first section (prefix) identifies a series of instruments. The last section (suffix) identifies a particular instrument within the series. If a letter is included with the serial number, it identifies the country in which the instrument was manufactured. If the serial prefix of your instrument differs from the one on the title page of this manual, a change sheet will be supplied to make this manual compatable with newer instruments or the backdating information in Appendix C will adapt this manual to earlier instruments. All correspondence with Hewlett-Packard should include the complete serial number.

1-13. 150 BAL MODIFICATION.

1-14. The Model 3555B is shipped from the factory with a 135 BAL function. If a 150 BAL function is desired instead of the 135 BAL function, the set can be converted by simply clipping a shorting wire within the set, applying a 150 BAL decal (supplied with the set) over the 135 BAL decal and making only one adjustment.

1-15. For detailed instructions on modification of the set refer to Paragraph 5-6.If your set is known to be within specification tolerances a simplified procedure can be used to modify the set and is described in Paragraph 3-69.

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