SIN-26      Licensed Material. Copyright I.P. Sharp Associates 1982
28 July 1982


TITLE:     IBM 3705 Hardware and Software Configuration

This SIN documents the 3705 hardware configuration required to run the SHARP Communications software and the information necessary to configure the operational software that will be loaded into the 3705.


An IBM 3705 running the SHARP communications software can connect the SHARP international, packet-switching network into a mainframe running SHARP APL. This provides local, error-free, access for asynchronous terminals from more than 60 locations around the world. In addition, the SHARP network is interconnected with the TYMNET, Telenet and DATAPAC networks.


A 3705 running the SHARP communications software can also connect local, asynchronous terminals into SHARP APL.


The SHARP communications software for the IBM 3705 is a stand-alone system that does not and cannot run under or with any other IBM 3705 software. In particular, the SHARP Communications software cannot run on the same 3705 as PEP or NCP.


Asynchronous terminals can also be connected to SHARP APL through an IBM 270x or any of its emulators (for example the IBM Emulator Program running on a 3705).





The 3705 must have a memory of 64K. 3705 models E02 and F02 have a 64K memory. The 3704 model A4 is also supported.




LIB - Line Interface Base. A LIB can hold 8 LINE SETS. A model A02 or E02 3705 can hold up to 4 LIBs. Adding a frame (model B02 or F02) to a 3705 will hold an additional 6 LIBs.


LINE SET         - Cables connecting modems to the LIB.


1A LINE SET - Supplies two cables, each supporting one half-duplex low-speed terminal. Hence a LIB with eight 1A Line Sets supports 16 terminals. 1A line sets can no longer be ordered from IBM and 1D line sets can be used instead. For a 1D line set used as a IA, order cable group #485.

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1B LINE SET - Supplies one cable to support a single full-duplex low-speed terminal. This does allow XON/XOFF support but the cost per terminal is twice the cost of a 1A line set. A 1D line set with cable group #492 or *473 may be used instead of a 1B line set.


1H LINE SET - Supplies cable to connect to a SHARP network link. The number of network terminals that can be supported depends on the baud rate of the line and the speed of the terminals. 1H line sets can no longer. be ordered from IBM. Order a 1D line set with cable group #473 instead.


1D LINE SET - Can be used as either 1A or 1H line set. A simple cable adapter is required when used as a 1H line set.


Business Machine Clock

- A clock is required for each different speed local terminal to be supported. The, possible speeds are 134.5, 300, and 1200 BPS.


The following is a correct 3705 configuration:

TYPE MODEL                 DESCRIPTION                            QUANTITY

3705 E02  Communications Controller        1

     1541 Chnl. Adpt. Type 1               1

     1642 Comm. Scanner Type 2             1

     1301 Attach. Base Type 1              1

     1302 Attach. Base Type 2              1

     4650 Business Machine Clock           2

(specify #9612(300bps) and#9608(1200bps))

4701 LIB Set Type 1                   2

4714 Line Set Type 1D                16

cable group #473                      1

cable group #485                     15

This configuration would support 30 local terminals and one high speed link to the network. The two business machine clocks handle 300 and 1200 baud local terminals. To support additional local terminals, one or two more LIBs could be ordered. With four LIBs in the first frame, the IPSANET connection is limited to 4800bps. This configuration does not support ASCII XOFF/XON flow control as the logical terminals are connected in half-duplex mode. If 134.5 baud (2741) support is required, specify a third business machine clock #9606.


If the number of local lines were to. exceed 62, then a second frame would have to be added, allowing attachment of 6 more LIBs.

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The physical and logical properties of an IBM 3705 are usually unique. These properties must be specified to the 3705 operational program. A 3705 configuration module is the vehicle used to specify these properties to the operational program. This document describes information which must be supplied before a 3705 configuration module can be prepared. Careful reading of this document will allow you to fill in the configuration form at the end of this document. This form will be used to provide a proper configuration for a specific 3705.




The 3705 is assumed to have exactly 64k bytes of storage, at least one type two communication scanner, and a channel adaptor of type one or four.




For every installed communication scanner, information about the installed business machine clocks and the line adapters must be supplied. A scanner may have from one to four business machine clocks installed. List the speeds of all business machine clocks in the scanner in the configuration form at the end of this document.


Connection to terminals or the network is made through line sets that are at particular line addresses. A line address is sometimes referred to as an ABAR (Adapter Base Address Register) address. A line address (ABAR address) is usually given as a hex number, but is sometimes given as POSx/PTn where 'x' and 'n' are decimal digits.


Connection to the SHARP network requires a 1H or 1D line set. List the line address of the 1H or 1D line set which will be used to connect the 3705 to the SHARP network in the configuration form.


1A and/or 1B linesets are used to attach local, asynchronous terminals to the 3705.


A feature called AUTOSPEED allows connection of a 300baud ASCII terminal or an IBM BCD/correspondence terminal (134.5 or 300baud) to a dial port. ASCII users must supply an initial letter 'o' to identify the terminal type. This is the recommended configuration for a dial port. 134.5 bps and 300 bps business machine clocks are a prerequisite for the AUTOSPEED feature.

For hardwired ports or ports which are attached to time division multiplexor, a predetermined speed and terminal type specification is most convenient for the terminal user. The predetermined terminal type is usually ASCII but can be BCD/corr. The predetermined speed must match an installed business machine clock.

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Full-duplex ASCII ports are supported via a 1B line set (or equivalent). One full-duplex port requires two ABAR addresses. 300bps and 1200bps are supported. Autospeed is not supported for full-duplex ports.


The addresses of the 1A and/or 1D lines and the uses to which these lines will be put must be specified in the configuration form.

A 30cps or 120cps ASCII terminal can be used as a psuedo-1052 logically attached to the NSC address. This is not recommended in a VM/370 environment.

The IBM view of a 3705 configuration may be described either by a 'field engineering configuration data sheet' or by 'machine history'. These documents specify line address and lineset type for all installed line adapters. For the first scanner, the IBM line addresses run from 020 to 04F. For the second scanner, the line addresses range from 0A0 to 0FF. The least significant hex digit gives the line number within a lib. The second digit gives lib number and two residue of scanner number.

The 3705 is attached to a byte multiplexor channel. Installation time strapping determines the device addresses which are recognized by a 3705. Two different kinds of channel address are used by the 3705:

NSC-The Native SubChannel address is used for loading the 3705 and the optional connection of a psuedo-1052. For an installation with more than one 3705 running SHARP communication software it is convenient to assign NSC addresses which have unique 256 residues.


ESC-The Emulator SubChannel addresses are used to connect asynchronous terminals to SHARP APE. The number of ESC addresses (TTASKS) allocated to a 3705 is the maximum number of terminals which can be simultaneously connected through the 3705. ESC addresses are used for both local 1A and 1D connections to APL and for network connections to APL. The number of ESC addresses assigned need not have any relationship to the number of 1A or 1D line sets installed. The ESC address range is determined by strapping within the channel adapter. The lowest ESC address must be a multiple of sixteen. The highest ESC address must be one less than a multiple of four. It is sometimes convenient to make the NSC address the same as the low ESC address. This makes the low ESC address unusable for APL but does place all of the device addresses for a particular 3705 in a compact block within the byte multiplexor address space. The NSC and ESC addresses must be entered into the configuration form.

The IBM engineer who installs the 3705 must be supplied with these subchannel addresses so that the machine can be properly strapped. If the 3705 channel strapping differs from the addresses supplied in the configuration, interface control checks can be expected on the byte multiplexor channel.

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q    Business Machine Clocks: ____ ____ ____ (134.5, 300, or 1200)

q    Network Connection Line Address: ____

q    Autospeed Line Addresses: ____ to ____

                             ____ to ____

q    Hardwired Line Addresses: ____ to ____ Type:____ Speed:____

                            ____ to ____ Type:____ Speed:____

                            ____ to ____ Type:____ Speed:____

q    NSC Channel Address: ____

q    ESC Addresses: ____ to ____

q    Preferred Network Address (3 or 4 characters):


(Users who access an in-house system from the I.P. Sharp network address of the 3705. This is an alphanumeric name of three or four characters.)




Some previous 3705 installations have required special cable assemblies. The most common special purpose cables serve to:


1.      Hardwire one operator terminal to a 3705 low speed line.

2.      Convert a half-duplex line set to full-duplex operation.


The following information provides electrical wiring instructions for both cables. Strain relief provisions may be desirable but are not documented here. The notation used assumes that each socket plug is designated by a letter. A decimal number preceding a letter describes a pin number within a socket or plug.


1. Terminal to 3705 cable requires two DB25S sockets (named AAB) and a six conductor cable. The 3705 can be attached to either socket. The wiring is:

2A     3B      

3A     2B      

4A     5A      

4B     5B      

6A     8A       20B

20A 6B        8B

7A     7B      

1A     1B       Sin26 - 5

2. The full-duplex adapter converts IBM cable group #485 (IBM P/N 5993200) to full-duplex (as in 1H or 1B line set) operation. Two DB25S sockets (named A and B) and one DB25P plug (named M) are required. Installation involves connecting the A^B sockets to the IBM A^B plugs and connecting the plug M to the modem socket. The wiring is:


2A 2M

4A 4M

5A 5M

15A 15M

20A 20M


3B 3M

6B 6M

8B 8M

17B 17M


6A 20B

7A 7B 7M

1A 1B 1M

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