Product Overview
Mitel MT8952BE HDLC Protocol Controller in a 28-Pin Plastic DIP, Marked With an 8714 Date Code
Condition
Used, removed from decommissioned equipment. The photograph shows a single 28-pin plastic DIP with a black molded body, the Mitel starburst logo, and three lines of marking that read MT8952BE, 35P013C6, and 8714 AE. The case is clean with no cracks, chips, or scorching, and the marking is crisp and fully legible. All 28 leads are present, bright, and in line, with no solder residue, flux, or discoloration visible in the photo. Against the millimeter rule the body measures approximately 36 to 37 mm long, consistent with a standard 28-pin 0.6 inch DIP. One piece in stock. Sold untested.
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Product Overview
The Mitel MT8952B is an ISO-CMOS HDLC protocol controller that handles bit-oriented protocol structure and formats data per the packet switching protocol defined in the X.25 (Level 2) recommendations of the CCITT. It transmits and receives packeted information or control data serially in a specific format, provides data transparency by zero insertion and deletion, and generates and detects flags, link channel states, and the abort sequence. Protocol functions can also be disabled to give transparent access to the serial bus through the parallel port. A microprocessor port with directly accessible registers handles setup and control, and a 19 byte FIFO sits in both the send and receive paths. The piece in hand carries the E suffix, MT8952BE, the 28 pin plastic DIP version of the family; Mitel also listed the MT8952BP in 28 pin PLCC and the MT8952BS in 28 pin SOIC. The second and third marking lines read 35P013C6 and 8714 AE, the latter in the year and week date code format that points to 1987.
Key Features
- Formats data as per X.25 (CCITT) level-2 standards
- Go-Ahead sequence generation and detection
- Single byte address recognition
- Microprocessor port and directly accessible registers for flexible operation and control
- 19 byte FIFO in both send and receive paths
- Handshake signals for multiplexing data links
- High speed serially clocked output at 2.5 Mbps
- ST-BUS compatibility with programmable channel selection for data and a separate timeslot for control information
- Independent watchdog timer
- Facility to disable protocol functions
- Low power ISO-CMOS technology
- Operating temperature: -40°C to +85°C
- Package: 28 pin plastic DIP (MT8952BE); family also offered as MT8952BP PLCC and MT8952BS SOIC
Applications
- Telecom repair technician rebuilding a line card in a legacy PBX and needing the original HDLC controller rather than a modern substitute
- Engineer maintaining a private packet network or digital set where the data link controller and protocol generator sit on an ST-BUS backplane
- ISDN hardware restorer replacing the D-channel controller on a basic access board
- Designer bringing up a C-channel controller against a Digital Network Interface Circuit, typically an MT8972
- Bench builder working an interprocessor communication link and wanting a 28-pin DIP that drops into a socket for probing
Frequently Asked Questions
Has this MT8952BE been tested?
No. It is a used pull from decommissioned equipment and it is sold untested. The visual inspection and the photograph are the extent of what we can confirm: intact body, legible marking, all 28 leads present and straight. Function is not confirmed. Verify against the Mitel datasheet and your own bench check before committing it to a board.
Which package is this, and can I swap it for an MT8952BP or MT8952BS?
This is the E suffix part, the 28 pin plastic DIP. The P suffix is 28 pin PLCC and the S suffix is 28 pin SOIC. Those are different footprints, so a DIP will not drop into a PLCC socket or an SOIC land pattern without an adapter. Check your board against the datasheet package drawing before you order.
What do the second and third marking lines mean?
The body reads MT8952BE on the first line, 35P013C6 on the second, and 8714 AE on the third. The 8714 reads as a year and week date code, which points to 1987 production. The 35P013C6 line is a Mitel internal trace or lot code; we do not have documentation for it and cannot decode it further.
Does it really run at 2.5 Mbps and handle ISDN D-channel work?
Those figures and applications come from the Mitel data for the MT8952B family: 2.5 Mbps high speed serially clocked output, D-channel controller for ISDN basic access, and C-channel controller to Digital Network Interface Circuits such as the MT8972. Nothing about this specific used piece has been measured here, so treat the published numbers as the design target and confirm behavior in your circuit.
What am I actually getting for a used, untested 1987 protocol controller?
Exactly one Mitel MT8952BE, the piece in the photograph, pulled from decommissioned equipment and not powered up here. You are taking on the function risk: it may work perfectly, and it may not. What you are not taking on is guesswork about identity or physical state, because the marking is legible in the photo, the leads are all there and straight, and the body is unbroken. That is the whole disclosure, and the photograph is the spec. For an obsolete X.25 level-2 part that no distributor stocks new, a clean, correctly marked pull that you socket and test is usually the fastest path back to a working board. Shipping is a flat $8, free once your order passes $28, and orders leave our Idaho warehouse the same or next business day.
Marked 8714, a code that points to 1987, and a chip like this one did the talking whenever a PBX had something to say in X.25 frames. If you are keeping an old switch or an ISDN line card breathing, here is the 28-pin piece that spoke that language.
