6.12 Communication Lines

6.12.1 BSC (
Preliminary 2703 BSC S
upport)

6.12.1.1 Function

This statement describes a BSC emulation line entry to either link 2 Hercules engines or a custom made
program emulating a 2780, 3780 or 3x74, or a custom made program interfacing to a real BSC line.

The communication is emulated over a TCP connection. All bytes are transferred as-is (except for
doubling DLE in transparent mode) just as over a real BSC link. Emulated EIA (DCD, DTR, CTS, etc.) or
X.21/V.11 leads (C, T, etc.) are treated differently depending on the DIAL option selected.

The line emulates a point-to-point BSC link. There is no point-to-multipoint handling.

6.12.1.2 Syntax

Descriptive

pe

hostname ipaddress port

hostname ipaddress port

-nnn

-1
nnn

-nnn

Diagram

Êʬ¬¬ ¬¬¬ ¬¬¬¬¬¬¬¬¬Ê

¬¬¬«

¬¬¬§¬¬¬¬¬¬¬¬¬Ê

hostname port

ipaddress

ʬ¬ hostname ¬¬¬§¬¬¬¬¬¬¬¬¬Ê

ipaddress port

ʬ¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬§¬¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬Ê

§¬¬¬ §¬¬¬ ¬¬¬«

¬¬¬¬¬«

-- 1 ¬¬¬¬
¬«

nnn nnn

ʬ¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬§¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬ÊÍ

§¬¬¬ ¬¬¬«

¬¬¬¬ ¬¬¬¬¬«

-1 ¬¬¬¬¬
«

nnn

6.12.1.3 Parameter

devaddr

This is the device address.

devtype

This is the device type. A valid device type is 2703.

DIAL=

This specifies the call direction (if any). If DIAL=NO is specified the TCP outgoing
connection is attempted as soon as an ENABLE CCW is executed. Also in this
mode, an incoming connection will always be accepted. If DIAL=IN or INOUT is
specified, a TCP incoming call is accepted only if an ENABLE CCW is currently
executing on the device. With DIAL=OUT the ENABLE CCW is rejected. When
DIAL=IN or INOUT is coded a DIAL CCW allows the application to establish a TCP
connection to a specific host. For other DIAL values the DIAL CCW is rejected.

LHOST=

Specifies which IP address to listen on. This also conditions the network interface
from which incoming calls will be accepted. An asterisk (“*”) means all incoming
TCP calls are accepted regardless of the destination IP address or call origin. A
given IP address when DIAL=OUT is specified has no effect.

LPORT=

Specifies the TCP port for which to listen to incoming TCP calls. This value is man-
datory for DIAL=IN, DIAL=INOUT or DIAL=NO. It is ignored for DIAL=OUT.

RHOST=

Specifies the remote host to which to direct a TCP connection on a DIAL=NO line
when an ENABLE CCW is executed. This value is mandatory when DIAL=NO is
specified, It is ignored for other DIAL values.

RPORT=

Specifies the remote port to which to direct a TCP connection on a DIAL=NO line
when an ENABLE CCW is executed. This value is mandatory when DIAL=NO is
specified, It is ignored for other DIAL values.

RTO=

Specifies the number of milliseconds before terminating a read on a timeout when
no read termination control character is received. A value of zero means the read
ends immediately. “-1” specifies that there is no timeout.

PTO=

Specifies the number of milliseconds before terminating a POLL on a timeout when
no ACK or NACK sequence is received. A value of zero means the POLL ends im-
mediately. “-1” specifies that there is no timeout.

ETO=

Specifies the number of milliseconds before terminating an ENABLE operation on a
timeout. The timeout applies when DIAL=NO, DIAL=IN or DIAL=INOUT is speci-
fied, , the outgoing TCP call fails (DIAL=NO) and there is no previously or currently
established TCP connection for this line. When DIAL=NO is specified the timeout
defaults to 10 seconds, for DIAL=IN or DIAL=INOUT, the timeout defaults to “-1”,
meaning there is no timeout.

RTO, PTO and ETO are tuning options. In most cases using the default values will give the best result.