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Azur Electronics

I bought this on eBay UK to do some research on a proposed RS-232 data communications system. The 4951C came complete with the HP 18180A Interface Pod and cables plus disks in the pouch. The original cost was $3,450 in 1987 plus $800 for Option 102, the 18180A. The Operating Manual and Service Manual are listed but not available for download.

Front view with protective cover fitted
Rear view
25 Way D Socket is for remote mode, either as a controller or slave unit. This can also be used to connect an ASCII Printer.

37 Way D Socket is to connect to the HP 18180A Interface Pod.

BNC Socket is to connect a RS-170 compatible Monitor.

The Interface Pod unclips from the front
The HP 18180A Interface Pod
The Keyboard hinges down
The HP 4951C is a portable data communications protocol analyser that contains the essential features required to install, maintain and design data networks up to 19.2kbps.

Cables and floppy disks contained in the Pouch
April 2013

Downloaded the Operating Manual (thanks Ron). Powered up and have the correct display after self tests completed.

Main Menu display
The 5" CRT display shows 16 lines of 32 characters. Softkeys occupy the bottom 2 lines. Green text on a black background.

Have quickly run through the Operating Manual and all seems to function as it should. The 4951C is a sophisticated data comms tester with monitoring, simulating and BERT (Bit Error Rate Testing) facilities for EIA RS-232C/CCITT V24 and RS-449/422A/423A. Comprehensive tests have not been done, but considered to be working ok. The Utilities Disk is required (this is not in DOS format so may be difficult to obtain). At the moment not sure if I will have a need for the 4951C or if I will resell it.

November 2016

Checking all the specialist batteries in my test equipment, see Batteries In Test Equipment. The Operating Manual notes "The 4951C contains a battery for maintaining current data and menu setups after turn off".

Need to check the Battery! Also be good to get a copy of the Service Manual.

Downloaded a copy of the Operating Manual and the Service Manual (thanks Glen). Both were available from www.hpmuseum.net which has a fascinating collection of HP computer information.

Top view with cover removed
Battery is located on the Memory Board
The 4951C has a 3.6V 0.065AHr NICAD Battery on the Memory Board, located underneath the Controller Board. Reference B1, Part No 1420-0264. Made by GE Co, Gold Top Data Sentry NiCd, Model No DS3GT, 3.6V.

The 4951C needs powering up occasionally to recharge the battery.

Decided not to utilise RS-232 for a communications system, so the 4951C is for sale.

February 2017